CloudLibrary allows you to check out up to 20 items at a time and have a hold list of at most 20 items.
Hoopla allows you to check out up to 10 items at a time, with a maximum check out limit of 10 items in any combination (ebooks, comics, audiobooks, movies/TV, music) per month.
At the beginning of the month, the check-out limit refreshes but any items that were checked out in the previous month remain checked out until their due date. Items in Hoopla are always available for check out, so there is no system for placing holds.