>If you've found the book but it isn't available you can search all your other cards by touching the two color card icon on the search result. It then searches for that book across your cards.

Amazing! I agree that this is not discoverable at all in the UI the last time I tried Libby.

That said, based on what nautilius said, searching at Overdrive.com is still superior because it properly searches across multiple libraries. (<https://www.reddit.com/r/books/comments/6uxca9/have_more_tha...>)