This is a big subject and some of my thoughts are -
Categorisation of digitally stored music can already be implemented by using name, file structure, and metadata tags. The B2 supports the first two methods but currently does not support metadata tags in a way that would help. The B2 does offer playlists to group your music together in whichever way you may want.
Metadata tags are not without issues if retrieved from public databases as the values are predominantly entered by the public and thus can, on occasion, be incorrect and also subjective.
e.g. a common tag is 'genre' and one persons categorisation of an album as 'Pop' may be another persons 'Rock'
Some streaming services also use information about your listening patterns to 'recommend' other music.
They will also guide you to music that fans of what you have favourited , have also favourited.
The streaming services are managing these 'crosslinks' via their own software and databases.
Some music management/playback software does support adding further categorisations to tracks in your music library and I think they are doing that via metadata tags.
I think tags are the way you might be able to do what you want but it will take a lot of work as entering the data will not be easily automated and I don't think you are going to see tags comprehensively implemented on the B2 anytime soon.
There is this online resource I found but again its subjective choice driven and populated, and, in my view, limited.
John