Cryptopunks

Cryptopunks are one of the earliest examples of a “Non-Fungible Token” on Ethereum, and were inspiration for the ERC-721 standard that powers most digital art and collectibles.The CryptoPunks are 10,000 uniquely created characters with no two exactly alike. Each character can be officially owned by a single person on the Ethereum blockchain. Originally, they could be claimed for free by anybody with an Ethereum wallet, but all 10,000 were quickly claimed. Now they must be purchased from someone via the marketplace.