I’ve written a 721 extension for creators to:
1: sign their nfts providing a secondary link between the nft and the object it represents beyond metadata. e.g. an artist can retain their key and post signatures over time that link back to the original signature on an owned nft, and owners can easily display and verify the nft is signed, much like an artist would sign a limited edition print.
2: verifiably introduce a total amount of nfts ever created (similar to total supply in 1155 but without the potential erc20 confusion).
Feedback very welcome! Thanks!