FLCL

It's a OVA across 6 episodes out of Gainax. It's finished airing, so the whole thing is watchable start to finish.

On the shelf it sits under Action, Comedy, and Mecha — worth knowing if you're comparing action anime specifically. If FLCL works for you, Attack on Titan and Demon Slayer: Kimetsu no Yaiba are close matches — see the full related list below.