A kind for music would make sense
Another sensible option would be agreed-on data formatting standards for the NIP-54 wikis that let them be used as an index for various types of data, such as song titles, artist names, album names, YouTube links, BitTorrent infohashes, nevent codes for nostr posts where artists posted songs on nostr, etc
Sadly when I started trying to make something like that happen, fiatjaf responded by breaking the NIP-54 wikis with asciidoc