Most of my exposure with anime was whatever was on Toonami and Adult Swim in the 2000s. I've not watched stuff like, Ghost In The Shell, Cowboy Bebop (only disjointed episodes out of order), Neon Genesis Evangelion, which I know are highly regarded.
I've seen just about every Miyazaki movie at this point. I've seen Akeria.
I'm sure there's more mainstream shows and non mainstream shows that I'm missing and would enjoy.
Thoughts?
Evangelion (followed by End of Evangelion), Madoka (followed by Madoka: Rebellion), One Punch Man, Mob Psycho 100, Redline, Cyberpunk: Edgerunners, Kaguya-sama: Love is War, Monthly Girls' Nozaki-kun.
Oh shit, everything but Evangelion is after 2010, uhhhhhhhhhh Legend of the Galactic Heroes! There, now I've got 3 decades covered.