I grew up with WB Loony Tunes (and Tex Avery and Superchicken and Wacky Racers and...), and that style of animation looks positively ancient in comparison to the modern animation style - whatever you call it - rendered as sort-of-3D. For example, Paw Patrol.
This actually worries me because I want my kid (currently 5yo) to have the benefit of the utter anarchy of Bugs Bunny and Daffy Duck and Roadrunner.
Some of them, Adventure time being a great example, can appeal to very young kids but they'll find new meaning in those episodes as they get older.
I think shows like Infinity Train, Avatar the Last Airbender/Legend of Korra, Steven Universe, and Samurai Jack will be better after a kid is old enough that Cocomelon wouldn't hold any appeal, but even at that age Sarah & Duck, Hilda, MLP, Craig of the Creek, etc could still be good. Just about anything that holds their attention and isn't Cocomelon is a huge win. If you'll enjoy it, all the better.
I'd also recommend getting your hands on the cartoons you enjoyed as a kid. Odds are good your kids will like them for the same reasons you did, although you may find that they don't all hold up for you.