[another device free night]
My Kindles has 15 collections... plus the can't be escaped 'My Clippings' and 'Dictionary'.
One of these is 'Admin' (user guides and other 'notices' from Kindle-on-high) - doesn't count.

There are less than 100 now because I read a few - and deleted some (well 7, but it's a start). That's the problem with virtuality, nearly 200 books - I'd have run out of space!
Current book, if it was a film I'd have switched off... 6 hours to go...