Shout out to @Akeldama, who continuously cleans up DistroKid (and other digital distributor labels). They are also uploading loads of high quality cover art scans, add new releases, fix and merge stuff.
What’s more is that they make use of the voting system 
When I started cleaning up DistroKid there were ca. 10 pages. I was nearly half way through and the next time I looked all the remaining stuff was done by them.