If you go down that route you might as well add “catalog numbers” of shops and (digital) distributors like these:
- https://musicbrainz.org/search?query=catno%3ATCJP*++%26%26+format%3A"digital+media"&type=release&limit=100&method=advanced (these are automatically generated by TuneCore Japan and not by the actual label)
- DLsite - MusicBrainz (NSFW)
- iTunes Store - MusicBrainz (most recent edit)
- Search Results - MusicBrainz (these are Record Union identifier)
Per How to Identify Labels - MusicBrainz distributors should generally be ignored and not added as release label