For the wacky antics it'd definitely be a tie between Ed Edd n' Eddy and Codename Kids Next Door. What other shows can you get a cursed telephone that causes suffering and an elevator made of junk that leads to the moon for EEnE? Or for KND have a whole zoo filled with kids as the exhibits so childless parents can throw peanuts at them while also having an episode where a man who looks like a baby use his cigar to connect to a global satellite web to try and turn everyone else into babies?
Samurai Pizza Cats. My grandma would have tapes of it so whenever I went over to my grandma's house, chances are this show would be playing at some point haha. The episode I remember the most is the one with the dragon.
This shouldn't be the answer because it's not really for kids. But it is, and will always be, The Simpsons.
Every evening at 6pm on UPN I would watch the Simpsons with my dad. I went from watching and understanding Bart to now watching with my daughter and seeing it through Homer's eyes.
It's a Dutch show that was beautifully drawn and animated in Japan. It still looks fantastic and it takes you seriously as the material is quite mature. It's about ww2, sort of like deep space 9. There's a lot of world exploration and adventure and it adresses societal issues. The only bummer is that the gender norms are quite old fashioned so it might not be appropriate for your kids based on your views.
As a kid in the '70s, all the cartoons on Wednesday afternoons kids matinee...Vicky the Viking, Maya the Bee, Heidi, Remi, Pink Panther & Hong Kong Phooey.
So many... The earliest cartoon I remember loving was The New Adventures of Winnie the Pooh. It was incredibly cozy. Then I discovered Cartoon Cartoons, especially Powerpuff Girls, Johnny Bravo, and Dexter's Laboratory with their throwback art styles, and got obsessed with those for a while.
Eventually SpongeBob came out and became my personality, because he was basically an annoying kid trying his best to be friends with everyone like I was. (It's played out now, it wasn't back then.)
ETA how did I not mention classic Looney Tunes. Before we had cable I was really into the classics.
This is a very big franchise in Asia but rarely mentioned in the west, so let me introduce it to (most of) you :>
Doraemon is a robot cat from the 22nd century who has gone back in time to help a kid named Nobita. He has a lot of wacky gadgets to offer. Each episode is basically a story about one of these gadgets. They also pump out a new movie every year.
Doraemon is incredibly popular in Spain, to the point that basically everyone no matter the age knows at least the premise and the main characters. It baffled me when I found out that it was largely unknown in other western countries.
Edit: I just remembered Shinchan, another anime that is huge in Spain but not very popular elsewhere.
A documentary was released on the show last month. During production they were given the original master tapes for the show and have been slowly releasing all of the episodes in glorious 4k for free on YouTube. Check them out - they hold up to nostalgia better than you'd expect.