Take a look at PUMAC Geometry B 2015/1 and AIME II 2007/3. Can you find other examples of this?
Update 2021-01-17: IOQM 2021/18 and USAMTS 03/04/11 (and apparently an old Chinese National HS ML question too, but I couldn’t find that). In fact, the IOQM problem was posted today!
Some other things: sign-up for Online Classes and take NICE.