NFTs on $ETH use token standards. ERC-721 creates one unique token per contract. Each token has a distinct ID. This powers CryptoPunks and Bored Apes. ERC-1155 mixes fungible and non-fungible tokens. One contract holds many token types. Gamers use this for swords, shields, and potions together. A single transaction can move 10 different items. Dynamic NFTs change over time. Their metadata updates based on real-world data. An NFT might grow stronger after you complete quests. Or it might reflect weather conditions. Soulbound tokens are non-transferable. They stay linked to one wallet forever. Universities issue these for degrees. Health records could use this model too. Each standard serves different needs. Choose based on whether tokens are unique, mixed, changing, or permanent. Understanding these models helps builders pick the right tool for their project. NFT #ERC721 #Blockchain