A unverisal blank entry
I propose a universal blank entry into the database. Kinda a catch-all for items that won't be added. In my instance, my foreign language books that are reprints of Marvel, but don't have a 1-to-1 English counterpart.
My idea is just a blank entry (with a $0.00 value) that can be added to collections. Then we can notate in the comment section what it is.