Seeing the success of Rare Pepes, John Watkinson and Matt Hall decided to create unique characters in a project called Cryptopunks. ‘Cryptopunks’ remains the only NFT project that used ERC-20 to launch. ERC-20 is the most common Ethereum Token Standard. However, it is not really ideal for creating unique tokens like NFTs. Thus, ERC721 was later introduced as the standard for NFTs on the Ethereum blockchain. Cryptopunk NFTs have become very valuable in the NFT space, given their historical value and scarcity. In fact, most of the highest-priced NFTs around are Cryptopunk NFTs.