I agree with Fullmetal Alchemist Brotherhood.

If anything the themes resonate more and more as I get older, and it's efficient with very little filler.

Kill La Kill is also fabulous to rewatch, similarly efficient and quick pace.

I really wish Ghost in the Shell held up better, but now that half that stuff is realistic it starts to feel more like a very human-rights violating cop drama. It was easier to have fun and ignore that when the universe they lived in was less real feeling.