I thought anti-* is the thing, but in the opposite way you would normally expect the thing, not just an unfinished version of the thing.

A library of unread books is still a library, in fact one should have a library of books you might want to read someday but haven’t yet, as part of the enjoyment of a library is coming across many things you’ve never read.

An anti-library might be a collection of things you could never read. A restricted place with all the books banned by a government, unorganized and uncategorized, inaccessible. Where books go to die.