I just discovered Library Elf today and I am testing it out with a couple of my library cards.
Library Elf allows you to track overdues and holds at certain libraries in Canada, U.S. and Internationally too. Toronto Public Library (TPL) is on this and its not even beta. Some of the other libraries I have cards at either aren’t on here or are beta, so I wouldn’t rely on the elves completely, but I think this would be helpful for me. If you’re interested, check it out and create your own account like I did and please if you do letme know what you think.