In the last years I have added to Musicbrainz many releases of the label La souterraine (Canada, francophone pop/experimental music). This label releases many single-artist albums and compilations for free/name your price on Bandcamp.
I am not going to add any more of their releases, but I suppose that some of you may be interested in continuing this work, so here is some info:
- Label website: http://souterraine.biz/
- Releases can be easily imported with Murdos’ userscripts for Bandcamp.
- On average 75% of the artists are not in Musicbrainz.
- There is backlog of about 100 releases (mostly LPs and compilations, some EPs).
- Most releases have a code such as
STRN-nnn.
Because many artists are not in the DB, adding a release requires a bit of effort and research. The reward is discovering some obscure gems. Oh, and helping MusicBrainz. 
It’s set as Paris, France in MB. 