Find keybase users based on my current signatures?

Would it be nice with an easy way to say "Find all keybase users who I _already_ have signed a key for" - in other words - people I've already verified - I'd like to find on keybase without manually finding all of them one by one.

The issue names no files, tests, or entry points. First clarify the discovery behavior and requirements for finding users whose keys the current user has signed; done means the requested users can be found without manually locating each one.

Written by the indexing model from the issue text.