[Feature Request] Collections auto-populated to list the content not in library as well

Collections were automatically created, however, a lot of them have only one item or otherwise incomplete. It would be great to be able to see from here what the missing items are. Even just a text-based list, no poster, would be sufficient. I didn’t have a good idea on UI to convey not-available in a dummy-proof way, so just text is enough for me.

For example, Constantine popped up as a Collection. After digging in to see if Collections were trying to bridge Movies and TV (which I do not have the TV show), I stepped back and just checked TMDB and found that there is a Constantine 2 in pre-production(!). So ideally I would have both listed when I opened the collection:
Constantine (2005) [with poster]
Constantine 2 (???) [text only]

Early 2021 clean-up: duplicate