I enjoyed this list of library ghosts, from britannica.com. Especially Lola (first bullet), who "helps find missing items." Is she the ghost of a librarian? One library in New Jersey issued a card for their resident ghost, which I think is very considerate, especially if she got the fee waived.

The Strathcona library in Edmonton is allegedly haunted, although I know very little about since I have yet to ever go on a ghost tour of old Strathcona. Maybe this year will be the year I finally make it.