Can you use Editor Icons in a game?

I wanted to make a game where some of the editor Icons are enemies and others are powerups, is that ok to do?

Not a legal advice, but most likely: No.

Any kind of editor code or editor resources belong to the licence you obtained from Unity. Editor stuff can’t and shouldn’t be shipped with the runtime. You don’t have a copyright on those assets.

So I would highly recommend to just find remakes of those icons where you actually have a licence to use them.