Dunno of any, but the CLI tools TMSU, Tocc, and Tagistant all create their own file systems (using symlinks) inside your drive's existing one that can then be accessed by other software. Pretty handy.
Software that stores it's own database of tags, as a way to consistently tag all sorts of files, no matter what metadata they support. I've tried some before for organising images and videos, and am currently trying some for organising music samples and sound effects.
I generally just use these tags:
TIT2
/ title
TPE1
/ artist
TALB
/ album
TPE2
/ albumartist
- Quod Libet labels this performer. Usually only use if there are multiple artists, software seems to sort stuff right otherwise.TYER
/ date
TPOS
/ discnumber
- If there are multiple.TCON
/ genre
- I have set genres I use, and I also place the country and sometimes city in here.TRCK
/ tracknumber
Ones that seem neat that I should use:
TSST
/ discsubtitle
TLAN
/ language
- Fill with three-letter language code from ISO-639-2mul
for multiple, zxx
for none.TSOP
/ artistsort
TSO2
/ albumartistsort
- Starting to try these two 'sort' tags now though.TSOT
/ titlesort
TSOA
/ albumsort
WOAF
/ ? - Track website.WOAR
/ ? - Track artist website. Well supported across file types.WOAS
/ ? - Source website.Maybe notable ones I don't bother with are:
TCOM
/ composer
TSOC
/ composersortorder
MVIN
/ movementnumber