Looking for a good book that would be harder to borrow

Hey there! First time poster here.
Here's the situation-I received some gift cards to a physical book store. I am an active Libby/Kindle user and don't mind waiting for new books for a reasonable amount of time. However, since I have some money to buy a few books right away, I'm looking for suggestions of books that would have really long wait times to borrow or are harder to find to borrow.

Essentially: What books would you pay money to skip the line for?