Sonic X, The Melancholy of Haruhi Suzumiya, Lucky Star, Nichijou and Sword Art Online tho more recently I'd add Serial Experiments Lain, BNA and Promare. Pokemon probably makes the list too especially since it was my actual first anime even tho I hadn't realized
I think with both Pokemon and Sonic the whole unlikely friendship aspect and the mixture of slice of life elements with lots of intense action and emotional moments made me want to also share stories that can be fun but also thrilling and moving and the same could be said of the rest too. I like the variety of style too, bouncing between cartoony and "childish" as well as more serious or intense looking visuals and overall just seeing stories with a variety of people is just really nice to watch
I think there's also that thing of seeing a story and enjoying it but also critiquing things like "i would have done this instead" or "something like this would be better" and stuff like that. i probably felt that a lot in moments with SAO or the Studio Trigger anime's I've been watching lately and i realize it's part of what led to me making certain stories, getting upset or confused by execution and wondering "how would i do that" or "what would make this better for my tastes"
there's probably others, like little drops, that added up filling that pool of inspiration and leaving their ripples so reflecting on that is really interesting