I’m going to go old-school here:

Magic Knight Rayearth - admittedly the manga was better since the anime had to do filler episodes, but the idea of a good story with no good guys or bad guys, and subtly riffing on RPG tropes, was an interesting watch. The OAV is a different take but also good (object censored nudity notwithstanding) and has a tighter storyline.

The Slayers - one of the anime that I first watched, so it holds a special place in my heart. Megumi does an amazing job as Lina.

Kimagure Orange Road - one of the earlier popular anime in the ‘love triangle’ genre, with the fun add-on that the main character secretly has esper powers. The characters are pretty well-rounded too.

Gundam Wing - yes, yes, but jokes aside it isone of the anime that made Mobile Suit shows popular outside of Japan; if you want to try out the Mobile Suit genre then it’s not a bad one to start with. Plus the Gundam designs are pretty cool, especially the Endless Waltz versions.

…And one more modern one: Spy x Family. It’s cute, dramatic, and the kid actually acts like a kid and not a mini-adult.