For really obscure content, internet archive, your library, usenet or even eBay are the go to!
> hey there's a project idea: a "todo list" for rippers that scrapes imdb and checks what's not in pirate ba
Private sites do things like this, archival efforts and have request systems.
Personally I do not feel guilty pirating a decades old TV show or movie. And I really doubt the industry cares much either.