Document attributes search

This is following on from a post in the Mac Technical Support forum.

I’d like to see a way to search documents based on attributes. I’m a heavy user of References, Snapshots and the like, and I’d love a way to return all documents that have certain attributes. With Notes (for instance) I can use (in Mac, not in Windows) the “Search In” plus * wildcard trick, but this isn’t possible for References or Snapshots.

At the moment, I can manually Label or Keyword the relevant docs, but this is pretty cumbersome and obviously not dynamic.