The Angry Beavers was by far my favorite.

Also loved Harvey Birdman: Attorney at Law.

Oh! Courage the Cowardly Dog

The last one that I can think of is probably Gundum Wing, although I watched a lot of Flinstones reruns growing up as well. Almost everything in both of them went way over my head as a kid.

So Hysteria was a bit hit and miss in terms of how enjoyable it was, but it did land at a time when I was able to record from TV and use it to aid some school presentations. Every single time the teachers would ask where I got this from.

I loved Cow and Chicken. The Red Guy was the best, I loved how he had lil butt cheeks you could see and went by names like “Mr Pants”.

Invader Zim

I still come back to this every once in a while. I loved the dark humor plus the childish humor mixed with some adult humor though I don’t feel it was on the same level as other shows of the same time as I’ve rewatched it, which has surprised me.

Do The Powerpuff Girls fit in this category? Really gory and with some inappropriate themes especially since they’re supposed to be little kindergarten age girls. Loved the show, I occasionally watch an episode as an adult.

Was also a fan of Billy and Mandy, nice to see that one as the post opener.

As for other shows, as a kid I loved watching Aeon Flux and I am still not sure wtf was going on in some of those episodes.

Moral Orel is another great show, smart and witty, although I discovered it as an adult.

Btw, if you’re still into animated shows, there’s a few communities around for them.

General animation:

!animation@lemm.ee

!adult_animation@lemmy.world

!animationafter30@lemmy.world

Japanese animation:

!anime@ani.social

Give’em some activity if you’re wanting to share and talk about some animated stuff you’ve been checking out!

It finished long before I was born (it was Saban’s “practice show” to test their confidence in taking on Power Rangers), but Samurai Pizza Cats was always avidly enjoyed by me, and it’s in fact one of the first kidult shows/franchises in the modern sense (if not the first) if I’m not mistaken, especially if you count only foreign content. Think Spongebob meets Teenage Mutant Ninja Turtles meets anime.

I can’t think of any shows that fit the bill that I’d say are my favorite that haven’t already been said. It also doesn’t help that my mind keeps going to Summer Camp Island for the later seasons when they start being less about random adventures and such and focus more on spoilery stuff. I wouldn’t consider it fully kidult (as per OPs description) but more like Bluey in that both kids and adults can enjoy it without the need for stuff flying over a kids head, despite the fact some non-inapproriate things might fly above their head.

Edit: Just read the growing up part. I’d say I was still growing up around 2019 already having graduated highschool and still have some growing up to do, so yeah.

Sabrina The Teenage Witch

Cartoon version of Sabrina, the witch. Salem the Cat is awesome and the best character besides the “What’s your favorite shaver” song dude

Samurai Jack, though not really from growing up… (Then again, when do we ever stop growing up? :)

It had great stories and beautiful artwork. But to an adult eye it was obvious that all those “robots” were there to keep it kid friendly.
All that oil was a clear stand-in for tons and tons of blood.

Adventure Time.

Steven Universe is one of my favorites.

Also, OK K.O.! Let’s Be Heroes is excellent, and created by Ian Jones-Quartey, the spouse of Steven Universe’s creator, Rebecca Sugar.

He used to write a webcomic that I followed a couple decades ago, which he officially ended in an episode of OK K.O. His webcomic was called RPG World.

Azumanga Daioh. Recently rewatched it and it’s still as funny today as it was in 2002.

Ren & Stimpy