I finally figured out how to search for collaborations using the Search Entities, but it’s really not intuitive:
It occurs to me that the tool for entering collaborations could be modified to search for collaborations:
Add a selector for what to search (recordings, releases, RGs, etc.), and you probably don’t need the Join Phrase, change ‘Done’ to ‘Search,’ and remove the Credits copy/paste buttons. A user could enter as many artists as they want to find tracks, releases, release groups, etc., where they are all credited.
What do you think?