Another thing I do with Ampys, is, I give one of each ampy to each girl as soon as she gets evolved. It helps telling the evolved and non-evolved apart, especially the 3* and 4* ones, which I rarely use, without having to double check for their state on the evolved tab.
This does cost quite a lot of ampies in the long run, but generally, whenever an event rewards ampies after the event is finished (so it doesn't use the shop or gacha system for trading tokens), I keep them in my inventory. Because of that, the stacks of ampies I have are always of equal size (currently it's 3 of each type, I hope we get a medal event again soon). Seperate ampies go to the girls I want to buff to insane amounts.