In a small way, I've been keeping collection-level links here: https://indology.info/external-resources/   , i.e., identifiably individual collections living at archive.org.  But there's a tremendous amount more than what I've noted.

The metadata (=catalogue data) at archive.org is notoriously bad, for perfectly understandable reasons.  Many people have thought about this issue, obviously, but it would be a very expensive undertaking to catalogue even a part of what's there and even at a minimal cataloguing record level.  The Archive.org people take the "Google search" approach, i.e., you find what you need by searching using carefully-constructed keywords.  This is surprisingly effective, but lots falls through the cracks, as we all know from personal experience.

My personal approach has been twofold:
  1. When I can, I add proper metadata in the "review" field.  And a permalink URL pointing to worldcat.org.
  2. Specifically for manuscripts, when I can, I add a link from PanditProject.org and vice-versa.
What I do is purely opportunistic and just a drop in the ocean, but it helps me in the long run, and may help others.

Best,
Dominik