ERC-721 standard introduced Non-Fungible Tokens implementations on the Ethereum blockchain system.

ERC-721 is an Ethereum Improvement Proposal Proposed by Dieter Shirley in late 2017. It allowed smart contracts to make use of Non-Fungible Tokens (NFT) for Ethereum Transactions. ERC-721 tokens are all unique and can have a different value than another Token in the same Contract.