ERC-721 is the token standard for non-fungible tokens on the Ethereum blockchain. Notable projects built using the ERC721 token standard include CryptoKitties and EtherTulips.
Timeline
This Ethereum Improvement Proposal laid the foundation of the ERC-721 standard, on which non-fungible tokens and cryptocollectibles are built (https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md)
People
Dieter Shirley
Wrote the ERC-721 specification
Nastassia Sachs
Wrote the ERC-721 specification
William Entriken
Wrote the ERC-721 specification
Further reading
Crypto Collectables? Ethereum's Next Killer App Is on Its Way
Alyssa Hertig
Web
The Anatomy of ERC721Understanding Non-Fungible Ethereum Tokens
Gerald Nash
Web