diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd715da5f38..0ad1a306796 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
  * `ERC2771Context`: use private variable from storage to store the forwarder address. Fixes issues where `_msgSender()` was not callable from constructors. ([#2754](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2754))
  * `EnumerableSet`: add `values()` functions that returns an array containing all values in a single call. ([#2768](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2768))
  * `Governor`: added a modular system of `Governor` contracts based on `GovernorAlpha` and `GovernorBravo`. ([#2672](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2672))
+ * Add an `interface` folder containing solidity interfaces to final ERCs. ([#2517](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2517))
 
 ## 4.2.0 (2021-06-30)
 
diff --git a/contracts/access/AccessControl.sol b/contracts/access/AccessControl.sol
index 5476c32803c..08ab65f687b 100644
--- a/contracts/access/AccessControl.sol
+++ b/contracts/access/AccessControl.sol
@@ -2,25 +2,11 @@
 
 pragma solidity ^0.8.0;
 
+import "./IAccessControl.sol";
 import "../utils/Context.sol";
 import "../utils/Strings.sol";
 import "../utils/introspection/ERC165.sol";
 
-/**
- * @dev External interface of AccessControl declared to support ERC165 detection.
- */
-interface IAccessControl {
-    function hasRole(bytes32 role, address account) external view returns (bool);
-
-    function getRoleAdmin(bytes32 role) external view returns (bytes32);
-
-    function grantRole(bytes32 role, address account) external;
-
-    function revokeRole(bytes32 role, address account) external;
-
-    function renounceRole(bytes32 role, address account) external;
-}
-
 /**
  * @dev Contract module that allows children to implement role-based access
  * control mechanisms. This is a lightweight version that doesn't allow enumerating role
@@ -69,33 +55,6 @@ abstract contract AccessControl is Context, IAccessControl, ERC165 {
 
     bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
 
-    /**
-     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
-     *
-     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
-     * {RoleAdminChanged} not being emitted signaling this.
-     *
-     * _Available since v3.1._
-     */
-    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
-
-    /**
-     * @dev Emitted when `account` is granted `role`.
-     *
-     * `sender` is the account that originated the contract call, an admin role
-     * bearer except when using {_setupRole}.
-     */
-    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
-
-    /**
-     * @dev Emitted when `account` is revoked `role`.
-     *
-     * `sender` is the account that originated the contract call:
-     *   - if using `revokeRole`, it is the admin role bearer
-     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
-     */
-    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
-
     /**
      * @dev Modifier that checks that an account has a specific role. Reverts
      * with a standardized message including the required role.
diff --git a/contracts/access/AccessControlEnumerable.sol b/contracts/access/AccessControlEnumerable.sol
index 64bb9a738de..6635a404990 100644
--- a/contracts/access/AccessControlEnumerable.sol
+++ b/contracts/access/AccessControlEnumerable.sol
@@ -2,18 +2,10 @@
 
 pragma solidity ^0.8.0;
 
+import "./IAccessControlEnumerable.sol";
 import "./AccessControl.sol";
 import "../utils/structs/EnumerableSet.sol";
 
-/**
- * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
- */
-interface IAccessControlEnumerable {
-    function getRoleMember(bytes32 role, uint256 index) external view returns (address);
-
-    function getRoleMemberCount(bytes32 role) external view returns (uint256);
-}
-
 /**
  * @dev Extension of {AccessControl} that allows enumerating the members of each role.
  */
@@ -56,7 +48,7 @@ abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessCon
     /**
      * @dev Overload {grantRole} to track enumerable memberships
      */
-    function grantRole(bytes32 role, address account) public virtual override {
+    function grantRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
         super.grantRole(role, account);
         _roleMembers[role].add(account);
     }
@@ -64,7 +56,7 @@ abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessCon
     /**
      * @dev Overload {revokeRole} to track enumerable memberships
      */
-    function revokeRole(bytes32 role, address account) public virtual override {
+    function revokeRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
         super.revokeRole(role, account);
         _roleMembers[role].remove(account);
     }
@@ -72,7 +64,7 @@ abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessCon
     /**
      * @dev Overload {renounceRole} to track enumerable memberships
      */
-    function renounceRole(bytes32 role, address account) public virtual override {
+    function renounceRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
         super.renounceRole(role, account);
         _roleMembers[role].remove(account);
     }
diff --git a/contracts/access/IAccessControl.sol b/contracts/access/IAccessControl.sol
new file mode 100644
index 00000000000..46147924361
--- /dev/null
+++ b/contracts/access/IAccessControl.sol
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+/**
+ * @dev External interface of AccessControl declared to support ERC165 detection.
+ */
+interface IAccessControl {
+    /**
+     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
+     *
+     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
+     * {RoleAdminChanged} not being emitted signaling this.
+     *
+     * _Available since v3.1._
+     */
+    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
+
+    /**
+     * @dev Emitted when `account` is granted `role`.
+     *
+     * `sender` is the account that originated the contract call, an admin role
+     * bearer except when using {AccessControl-_setupRole}.
+     */
+    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
+
+    /**
+     * @dev Emitted when `account` is revoked `role`.
+     *
+     * `sender` is the account that originated the contract call:
+     *   - if using `revokeRole`, it is the admin role bearer
+     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
+     */
+    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
+
+    /**
+     * @dev Returns `true` if `account` has been granted `role`.
+     */
+    function hasRole(bytes32 role, address account) external view returns (bool);
+
+    /**
+     * @dev Returns the admin role that controls `role`. See {grantRole} and
+     * {revokeRole}.
+     *
+     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
+     */
+    function getRoleAdmin(bytes32 role) external view returns (bytes32);
+
+    /**
+     * @dev Grants `role` to `account`.
+     *
+     * If `account` had not been already granted `role`, emits a {RoleGranted}
+     * event.
+     *
+     * Requirements:
+     *
+     * - the caller must have ``role``'s admin role.
+     */
+    function grantRole(bytes32 role, address account) external;
+
+    /**
+     * @dev Revokes `role` from `account`.
+     *
+     * If `account` had been granted `role`, emits a {RoleRevoked} event.
+     *
+     * Requirements:
+     *
+     * - the caller must have ``role``'s admin role.
+     */
+    function revokeRole(bytes32 role, address account) external;
+
+    /**
+     * @dev Revokes `role` from the calling account.
+     *
+     * Roles are often managed via {grantRole} and {revokeRole}: this function's
+     * purpose is to provide a mechanism for accounts to lose their privileges
+     * if they are compromised (such as when a trusted device is misplaced).
+     *
+     * If the calling account had been granted `role`, emits a {RoleRevoked}
+     * event.
+     *
+     * Requirements:
+     *
+     * - the caller must be `account`.
+     */
+    function renounceRole(bytes32 role, address account) external;
+}
diff --git a/contracts/access/IAccessControlEnumerable.sol b/contracts/access/IAccessControlEnumerable.sol
new file mode 100644
index 00000000000..e4a8e9fba02
--- /dev/null
+++ b/contracts/access/IAccessControlEnumerable.sol
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "./IAccessControl.sol";
+
+/**
+ * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
+ */
+interface IAccessControlEnumerable is IAccessControl {
+    /**
+     * @dev Returns one of the accounts that have `role`. `index` must be a
+     * value between 0 and {getRoleMemberCount}, non-inclusive.
+     *
+     * Role bearers are not sorted in any particular way, and their ordering may
+     * change at any point.
+     *
+     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
+     * you perform all queries on the same block. See the following
+     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
+     * for more information.
+     */
+    function getRoleMember(bytes32 role, uint256 index) external view returns (address);
+
+    /**
+     * @dev Returns the number of accounts that have `role`. Can be used
+     * together with {getRoleMember} to enumerate all bearers of a role.
+     */
+    function getRoleMemberCount(bytes32 role) external view returns (uint256);
+}
diff --git a/contracts/access/README.adoc b/contracts/access/README.adoc
index ed8dcc5a5d6..2e84c09ad43 100644
--- a/contracts/access/README.adoc
+++ b/contracts/access/README.adoc
@@ -12,6 +12,10 @@ This directory provides ways to restrict who can access the functions of a contr
 
 {{Ownable}}
 
+{{IAccessControl}}
+
 {{AccessControl}}
 
+{{IAccessControlEnumerable}}
+
 {{AccessControlEnumerable}}
diff --git a/contracts/interfaces/IERC1155.sol b/contracts/interfaces/IERC1155.sol
new file mode 100644
index 00000000000..9522849a8a1
--- /dev/null
+++ b/contracts/interfaces/IERC1155.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC1155/IERC1155.sol";
diff --git a/contracts/interfaces/IERC1155MetadataURI.sol b/contracts/interfaces/IERC1155MetadataURI.sol
new file mode 100644
index 00000000000..2e10d3b8378
--- /dev/null
+++ b/contracts/interfaces/IERC1155MetadataURI.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC1155/extensions/IERC1155MetadataURI.sol";
diff --git a/contracts/interfaces/IERC1155Receiver.sol b/contracts/interfaces/IERC1155Receiver.sol
new file mode 100644
index 00000000000..79941cf577f
--- /dev/null
+++ b/contracts/interfaces/IERC1155Receiver.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC1155/IERC1155Receiver.sol";
diff --git a/contracts/interfaces/IERC1363.sol b/contracts/interfaces/IERC1363.sol
new file mode 100644
index 00000000000..7fafc8fe0d5
--- /dev/null
+++ b/contracts/interfaces/IERC1363.sol
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "./IERC20.sol";
+import "./IERC165.sol";
+
+interface IERC1363 is IERC165, IERC20 {
+    /*
+     * Note: the ERC-165 identifier for this interface is 0x4bbee2df.
+     * 0x4bbee2df ===
+     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
+     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
+     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
+     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)'))
+     */
+
+    /*
+     * Note: the ERC-165 identifier for this interface is 0xfb9ec8ce.
+     * 0xfb9ec8ce ===
+     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
+     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
+     */
+
+    /**
+     * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
+     * @param to address The address which you want to transfer to
+     * @param value uint256 The amount of tokens to be transferred
+     * @return true unless throwing
+     */
+    function transferAndCall(address to, uint256 value) external returns (bool);
+
+    /**
+     * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
+     * @param to address The address which you want to transfer to
+     * @param value uint256 The amount of tokens to be transferred
+     * @param data bytes Additional data with no specified format, sent in call to `to`
+     * @return true unless throwing
+     */
+    function transferAndCall(
+        address to,
+        uint256 value,
+        bytes memory data
+    ) external returns (bool);
+
+    /**
+     * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver
+     * @param from address The address which you want to send tokens from
+     * @param to address The address which you want to transfer to
+     * @param value uint256 The amount of tokens to be transferred
+     * @return true unless throwing
+     */
+    function transferFromAndCall(
+        address from,
+        address to,
+        uint256 value
+    ) external returns (bool);
+
+    /**
+     * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver
+     * @param from address The address which you want to send tokens from
+     * @param to address The address which you want to transfer to
+     * @param value uint256 The amount of tokens to be transferred
+     * @param data bytes Additional data with no specified format, sent in call to `to`
+     * @return true unless throwing
+     */
+    function transferFromAndCall(
+        address from,
+        address to,
+        uint256 value,
+        bytes memory data
+    ) external returns (bool);
+
+    /**
+     * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
+     * and then call `onApprovalReceived` on spender.
+     * @param spender address The address which will spend the funds
+     * @param value uint256 The amount of tokens to be spent
+     */
+    function approveAndCall(address spender, uint256 value) external returns (bool);
+
+    /**
+     * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
+     * and then call `onApprovalReceived` on spender.
+     * @param spender address The address which will spend the funds
+     * @param value uint256 The amount of tokens to be spent
+     * @param data bytes Additional data with no specified format, sent in call to `spender`
+     */
+    function approveAndCall(
+        address spender,
+        uint256 value,
+        bytes memory data
+    ) external returns (bool);
+}
diff --git a/contracts/interfaces/IERC1363Receiver.sol b/contracts/interfaces/IERC1363Receiver.sol
new file mode 100644
index 00000000000..1e9b3d49478
--- /dev/null
+++ b/contracts/interfaces/IERC1363Receiver.sol
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+interface IERC1363Receiver {
+    /*
+     * Note: the ERC-165 identifier for this interface is 0x88a7ca5c.
+     * 0x88a7ca5c === bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))
+     */
+
+    /**
+     * @notice Handle the receipt of ERC1363 tokens
+     * @dev Any ERC1363 smart contract calls this function on the recipient
+     * after a `transfer` or a `transferFrom`. This function MAY throw to revert and reject the
+     * transfer. Return of other than the magic value MUST result in the
+     * transaction being reverted.
+     * Note: the token contract address is always the message sender.
+     * @param operator address The address which called `transferAndCall` or `transferFromAndCall` function
+     * @param from address The address which are token transferred from
+     * @param value uint256 The amount of tokens transferred
+     * @param data bytes Additional data with no specified format
+     * @return `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))`
+     *  unless throwing
+     */
+    function onTransferReceived(
+        address operator,
+        address from,
+        uint256 value,
+        bytes memory data
+    ) external returns (bytes4);
+}
diff --git a/contracts/interfaces/IERC1363Spender.sol b/contracts/interfaces/IERC1363Spender.sol
new file mode 100644
index 00000000000..fb58ffc6021
--- /dev/null
+++ b/contracts/interfaces/IERC1363Spender.sol
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+interface IERC1363Spender {
+    /*
+     * Note: the ERC-165 identifier for this interface is 0x7b04a2d0.
+     * 0x7b04a2d0 === bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))
+     */
+
+    /**
+     * @notice Handle the approval of ERC1363 tokens
+     * @dev Any ERC1363 smart contract calls this function on the recipient
+     * after an `approve`. This function MAY throw to revert and reject the
+     * approval. Return of other than the magic value MUST result in the
+     * transaction being reverted.
+     * Note: the token contract address is always the message sender.
+     * @param owner address The address which called `approveAndCall` function
+     * @param value uint256 The amount of tokens to be spent
+     * @param data bytes Additional data with no specified format
+     * @return `bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))`
+     *  unless throwing
+     */
+    function onApprovalReceived(
+        address owner,
+        uint256 value,
+        bytes memory data
+    ) external returns (bytes4);
+}
diff --git a/contracts/interfaces/IERC165.sol b/contracts/interfaces/IERC165.sol
new file mode 100644
index 00000000000..e9f6b057ad8
--- /dev/null
+++ b/contracts/interfaces/IERC165.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../utils/introspection/IERC165.sol";
diff --git a/contracts/interfaces/IERC1820Implementer.sol b/contracts/interfaces/IERC1820Implementer.sol
new file mode 100644
index 00000000000..ead56245a36
--- /dev/null
+++ b/contracts/interfaces/IERC1820Implementer.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../utils/introspection/IERC1820Implementer.sol";
diff --git a/contracts/interfaces/IERC1820Registry.sol b/contracts/interfaces/IERC1820Registry.sol
new file mode 100644
index 00000000000..77341290bd8
--- /dev/null
+++ b/contracts/interfaces/IERC1820Registry.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../utils/introspection/IERC1820Registry.sol";
diff --git a/contracts/interfaces/IERC20.sol b/contracts/interfaces/IERC20.sol
new file mode 100644
index 00000000000..0072add5e29
--- /dev/null
+++ b/contracts/interfaces/IERC20.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC20/IERC20.sol";
diff --git a/contracts/interfaces/IERC20Metadata.sol b/contracts/interfaces/IERC20Metadata.sol
new file mode 100644
index 00000000000..8b72362908a
--- /dev/null
+++ b/contracts/interfaces/IERC20Metadata.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC20/extensions/IERC20Metadata.sol";
diff --git a/contracts/interfaces/IERC2981.sol b/contracts/interfaces/IERC2981.sol
new file mode 100644
index 00000000000..0ea8844552f
--- /dev/null
+++ b/contracts/interfaces/IERC2981.sol
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "./IERC165.sol";
+
+/**
+ * @dev Interface for the NFT Royalty Standard
+ */
+interface IERC2981 is IERC165 {
+    /**
+     * @notice Called with the sale price to determine how much royalty is owed and to whom.
+     * @param tokenId - the NFT asset queried for royalty information
+     * @param salePrice - the sale price of the NFT asset specified by `tokenId`
+     * @return receiver - address of who should be sent the royalty payment
+     * @return royaltyAmount - the royalty payment amount for `salePrice`
+     */
+    function royaltyInfo(uint256 tokenId, uint256 salePrice)
+        external
+        view
+        returns (address receiver, uint256 royaltyAmount);
+}
diff --git a/contracts/interfaces/IERC3156.sol b/contracts/interfaces/IERC3156.sol
index ad970d43248..36d64d5ec4d 100644
--- a/contracts/interfaces/IERC3156.sol
+++ b/contracts/interfaces/IERC3156.sol
@@ -2,62 +2,5 @@
 
 pragma solidity ^0.8.0;
 
-/**
- * @dev Interface of the ERC3156 FlashBorrower, as defined in
- * https://eips.ethereum.org/EIPS/eip-3156[ERC-3156].
- *
- * _Available since v4.1._
- */
-interface IERC3156FlashBorrower {
-    /**
-     * @dev Receive a flash loan.
-     * @param initiator The initiator of the loan.
-     * @param token The loan currency.
-     * @param amount The amount of tokens lent.
-     * @param fee The additional amount of tokens to repay.
-     * @param data Arbitrary data structure, intended to contain user-defined parameters.
-     * @return The keccak256 hash of "ERC3156FlashBorrower.onFlashLoan"
-     */
-    function onFlashLoan(
-        address initiator,
-        address token,
-        uint256 amount,
-        uint256 fee,
-        bytes calldata data
-    ) external returns (bytes32);
-}
-
-/**
- * @dev Interface of the ERC3156 FlashLender, as defined in
- * https://eips.ethereum.org/EIPS/eip-3156[ERC-3156].
- */
-interface IERC3156FlashLender {
-    /**
-     * @dev The amount of currency available to be lended.
-     * @param token The loan currency.
-     * @return The amount of `token` that can be borrowed.
-     */
-    function maxFlashLoan(address token) external view returns (uint256);
-
-    /**
-     * @dev The fee to be charged for a given loan.
-     * @param token The loan currency.
-     * @param amount The amount of tokens lent.
-     * @return The amount of `token` to be charged for the loan, on top of the returned principal.
-     */
-    function flashFee(address token, uint256 amount) external view returns (uint256);
-
-    /**
-     * @dev Initiate a flash loan.
-     * @param receiver The receiver of the tokens in the loan, and the receiver of the callback.
-     * @param token The loan currency.
-     * @param amount The amount of tokens lent.
-     * @param data Arbitrary data structure, intended to contain user-defined parameters.
-     */
-    function flashLoan(
-        IERC3156FlashBorrower receiver,
-        address token,
-        uint256 amount,
-        bytes calldata data
-    ) external returns (bool);
-}
+import "./IERC3156FlashBorrower.sol";
+import "./IERC3156FlashLender.sol";
diff --git a/contracts/interfaces/IERC3156FlashBorrower.sol b/contracts/interfaces/IERC3156FlashBorrower.sol
new file mode 100644
index 00000000000..fb247468c88
--- /dev/null
+++ b/contracts/interfaces/IERC3156FlashBorrower.sol
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+/**
+ * @dev Interface of the ERC3156 FlashBorrower, as defined in
+ * https://eips.ethereum.org/EIPS/eip-3156[ERC-3156].
+ *
+ * _Available since v4.1._
+ */
+interface IERC3156FlashBorrower {
+    /**
+     * @dev Receive a flash loan.
+     * @param initiator The initiator of the loan.
+     * @param token The loan currency.
+     * @param amount The amount of tokens lent.
+     * @param fee The additional amount of tokens to repay.
+     * @param data Arbitrary data structure, intended to contain user-defined parameters.
+     * @return The keccak256 hash of "ERC3156FlashBorrower.onFlashLoan"
+     */
+    function onFlashLoan(
+        address initiator,
+        address token,
+        uint256 amount,
+        uint256 fee,
+        bytes calldata data
+    ) external returns (bytes32);
+}
diff --git a/contracts/interfaces/IERC3156FlashLender.sol b/contracts/interfaces/IERC3156FlashLender.sol
new file mode 100644
index 00000000000..8041ddbaccf
--- /dev/null
+++ b/contracts/interfaces/IERC3156FlashLender.sol
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "./IERC3156FlashBorrower.sol";
+
+/**
+ * @dev Interface of the ERC3156 FlashLender, as defined in
+ * https://eips.ethereum.org/EIPS/eip-3156[ERC-3156].
+ *
+ * _Available since v4.1._
+ */
+interface IERC3156FlashLender {
+    /**
+     * @dev The amount of currency available to be lended.
+     * @param token The loan currency.
+     * @return The amount of `token` that can be borrowed.
+     */
+    function maxFlashLoan(address token) external view returns (uint256);
+
+    /**
+     * @dev The fee to be charged for a given loan.
+     * @param token The loan currency.
+     * @param amount The amount of tokens lent.
+     * @return The amount of `token` to be charged for the loan, on top of the returned principal.
+     */
+    function flashFee(address token, uint256 amount) external view returns (uint256);
+
+    /**
+     * @dev Initiate a flash loan.
+     * @param receiver The receiver of the tokens in the loan, and the receiver of the callback.
+     * @param token The loan currency.
+     * @param amount The amount of tokens lent.
+     * @param data Arbitrary data structure, intended to contain user-defined parameters.
+     */
+    function flashLoan(
+        IERC3156FlashBorrower receiver,
+        address token,
+        uint256 amount,
+        bytes calldata data
+    ) external returns (bool);
+}
diff --git a/contracts/interfaces/IERC721.sol b/contracts/interfaces/IERC721.sol
new file mode 100644
index 00000000000..8e763e61fe0
--- /dev/null
+++ b/contracts/interfaces/IERC721.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC721/IERC721.sol";
diff --git a/contracts/interfaces/IERC721Enumerable.sol b/contracts/interfaces/IERC721Enumerable.sol
new file mode 100644
index 00000000000..db01d877378
--- /dev/null
+++ b/contracts/interfaces/IERC721Enumerable.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC721/extensions/IERC721Enumerable.sol";
diff --git a/contracts/interfaces/IERC721Metadata.sol b/contracts/interfaces/IERC721Metadata.sol
new file mode 100644
index 00000000000..7265be01a88
--- /dev/null
+++ b/contracts/interfaces/IERC721Metadata.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC721/extensions/IERC721Metadata.sol";
diff --git a/contracts/interfaces/IERC721Receiver.sol b/contracts/interfaces/IERC721Receiver.sol
new file mode 100644
index 00000000000..e23d986be5c
--- /dev/null
+++ b/contracts/interfaces/IERC721Receiver.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC721/IERC721Receiver.sol";
diff --git a/contracts/interfaces/IERC777.sol b/contracts/interfaces/IERC777.sol
new file mode 100644
index 00000000000..88f7792f3f3
--- /dev/null
+++ b/contracts/interfaces/IERC777.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC777/IERC777.sol";
diff --git a/contracts/interfaces/IERC777Recipient.sol b/contracts/interfaces/IERC777Recipient.sol
new file mode 100644
index 00000000000..23d7e7b005b
--- /dev/null
+++ b/contracts/interfaces/IERC777Recipient.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC777/IERC777Recipient.sol";
diff --git a/contracts/interfaces/IERC777Sender.sol b/contracts/interfaces/IERC777Sender.sol
new file mode 100644
index 00000000000..ffd3fec581c
--- /dev/null
+++ b/contracts/interfaces/IERC777Sender.sol
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC777/IERC777Sender.sol";
diff --git a/contracts/interfaces/README.adoc b/contracts/interfaces/README.adoc
new file mode 100644
index 00000000000..943b43235f3
--- /dev/null
+++ b/contracts/interfaces/README.adoc
@@ -0,0 +1,50 @@
+= Interfaces
+
+[.readme-notice]
+NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/api/utils
+
+== List of standardized interfaces
+These interfaces are available as `.sol` files, and also as compiler `.json` ABI files (through the npm package). These
+are usefull to interract with third party contracts that implement them.
+
+- {IERC20}
+- {IERC20Metadata}
+- {IERC165}
+- {IERC721}
+- {IERC721Receiver}
+- {IERC721Enumerable}
+- {IERC721Metadata}
+- {IERC777}
+- {IERC777Recipient}
+- {IERC777Sender}
+- {IERC1155}
+- {IERC1155Receiver}
+- {IERC1155MetadataURI}
+- {IERC1271}
+- {IERC1363}
+- {IERC1820Implementer}
+- {IERC1820Registry}
+- {IERC2612}
+- {IERC2981}
+- {IERC3156FlashLender}
+- {IERC3156FlashBorrower}
+
+== Detailed ABI
+
+{{IERC1271}}
+
+{{IERC1363}}
+
+{{IERC1363Receiver}}
+
+{{IERC1820Implementer}}
+
+{{IERC1820Registry}}
+
+{{IERC2612}}
+
+{{IERC2981}}
+
+{{IERC3156FlashLender}}
+
+{{IERC3156FlashBorrower}}
diff --git a/contracts/interfaces/draft-IERC2612.sol b/contracts/interfaces/draft-IERC2612.sol
new file mode 100644
index 00000000000..83a80ac93ff
--- /dev/null
+++ b/contracts/interfaces/draft-IERC2612.sol
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../token/ERC20/extensions/draft-IERC20Permit.sol";
+
+interface IERC2612 is IERC20Permit {}