How can you forget this one!

– Are you ready kids?
Aye, aye Captain
I can't hear you
Aye, aye Captain

Ohhhh
Who lives in a pineapple under the sea?
SpongeBob SquarePants

Absorbent and yellow and porous is he
SpongeBob SquarePants

If nautical nonsense be something you wish
SpongeBob SquarePants

Then drop on the deck and flop like a fish!
(SpongeBob SquarePants) ready?

SpongeBob SquarePants
SpongeBob SquarePants
SpongeBob SquarePants
SpongeBob SquarePants –

I'm surprised you didn't include this in the list because it's one of the catchiest songs ever. But I agree with what you said. Theme songs from back then bring back such strong nostalgia, I don't think it's possible to not like any of them from that era. Good old times!

I also absolutely love Scooby-Doo theme song too! And oh, The Powerpuff Girls!