Easily Mob Psycho 100. It's way above anything else for me. Tons of incredible action cuts, a quality that somehow stays consistent throughout its entire run (unlike most other shows where you get a cool action shot once every 10 episodes), as well as the inclusion of a bunch of non traditional animation techniques using things like oil painting, painting on glass, or even animating with sand. Plus it's super well written
Some other recommendations:
Space Dandy - Essentially an anthology where every episode is directed by a different star anime director. Gives you a ton of variety both in terms of writing and in terms of visuals, and almost every episode looks incredible.
Yozakura Quarter: Hana no Uta - if you can stomach the absurd amount of fanservice, this (and the OVA Hoshi no Umi) have some pretty great action cuts.
Maquia - This movie sort of got lost between all the Kyo-ani and Shinkai movies coming out lately, but it absolutely stands shoulder to shoulder with these more famous examples ( I like it more than them to be honest). Super beautiful visually, with great character animation, beautiful backgrounds, and character design by Akihiko Yoshida.
Gankutsuou - If by "animation" you mean motion, then you wont really find too much of that here. But in terms of having a unique defining visual identity, Gankutsuou really stands out, thanks to great character design and the fact that is uses some sort of weird texturing effect instead of traditional coloring.
Sound Euphonium - Kyo-Ani makes a lot of good looking shows, but this one is by far my favourite thanks to the incredible attention to detail during the musical performances.
Kizumonogatari movies - The Monogatari franchise isn't really something that I'd recommend people for the plot, and the visual quality of the TV series has sort of gone down the drain after the original show. But the movies look absolutely incredible.
Land of the Lustrous and Beastars - 3D GC in anime has a pretty bad reputation, but these two shows actually manage to use CG to their advantage. They're still far behind what you see in videogames or western CG productions, but they show GC can have a place in anime.