No support for Punks, Kitties, and ERC-1155s
CryptoPunks and CryptoKitties came before the ERC-721 standard and thus do not support them. A lot of new NFTs follow the ERC-1155 standard rather than the ERC-721 standard. Consider adding Putty-specific wrappers for these sorts of NFTs so that your users don't have to look elsewhere to sell their NFTs
Judge has assessed an item in Issue #228 as Medium risk. The relevant finding follows: