Type, or speak the book IDs under various categories like "Books in Shelf", "Books in Circulation", etc, and after entering all of the stock, you can find the missing books as well as share them.
When you have a huge library, many stock verifiers can install this app, and enter the data. Once done, they may export all the data and share it with their leader who can import every individual's data and find the missing books.
Note: This app addresses a specific design problem of data entry with a large number of books, and so this may not address your use case. If you feel so, please contact me instead of giving a bad rating. Thank you!