Saturday Morning Cartoon Campaign...

[jmucchiello]

Thundar the Barbarian
Goltar and The Golden Lance
The D&D Cartoon
He Man
Thundercats

Today, you would call this a Boomerang Campaign as my 4-year old son watches some of these on Boomerang all the time. But don't watch the source material yourself. It is cringeworthy.

 

[Herobizkit]

Clearly not exactly what you're looking for, but the Gummi Bears featured all kinds of tech that was more advanced than it "should" be while still being "medieval". Good stuff.