Almost every anime with romance as the main aspect.

Toradora, Kimi no Na Wa, Kaguya Sama.

I feel like every single thing that japanese mangaka's can come up with are toxic human relationships. The only romance story i liked was Jitsu Wa Watashi Wa (manga) and it was because it was vanilla as hell. I think i simply don't like everything being solved because "they like each other at the end", "they will end up together despite the horrible things X did to Y several times" or their relationship dynamic being incredibly toxic like "love is war" or also "they like each other because the writter said so".

Hell in Jitsu Wa both MC aknowledged what they liked from each other in one or two scenes making their love far more believable.