https://developers.metaplex.com/core

https://github.com/metaplex-foundation/mpl-core

Metaplex Core (“Core”) sheds the complexity and technical debt of previous standards and provides a clean and simple core spec for digital assets. This next generation Solana NFT standard uses a single account design, reducing minting costs and improving Solana network load compared to alternatives. It also has a flexible plugin system that allows for developers to modify the behavior and functionality of assets.