The Fantastic Four have appeared on quite a few of the other Marvel cartoons. Here are summeries of those apperances.
The whole team appeared in the season 1 episode "Fantastic Fortitude." The Hulk and She-Hulk were travelling to New York to see if Reed could help cure them both. However, everyone but the Thing had already left on vacation (but they did appear briefly). The rest of the episode had the Hulk, She-Hulk, and the Thing teaming up to stop the Leader's Gamma Mutant Warriors, led by the Ogress. Both Beau Weaver and Chuck McCann reprised their roles for this episode.
In the fifth
season of his show, Spider-Man was sent to the Secret Wars by the Beyonder
and Madame Web. This was done to see if he was a great leader, which was
eventually proven. His task was to lead a group of heroes of his choosing
against a tough group of villains. Because the Beyonder and Madame Web had
chosen Doctor Doom as of the villains, Spider-Man realized that the only
people who could help take him down were the Fantastic Four. A whole episode,
called "Doom," involved this fight. In it, Ben went over to Doom's side,
since he cured him of being the Thing. Doom would steal the Beyonder's power,
but would not be able to control it, resulting in a climatic battle.
Unfortunately only one of the voice actors from the show came on for the Secret Wars. Quinton Flynn, the second Human Torch, reprised his role. The others were replaced by new actors. Cam Clarke, Gail Matthius, and Pat Pinney replaced Mister Fantastic, Invisible Woman, and the Thing respectively. Doctor Doom was voiced by Tom Kane, who played H.O.M.E.R. on Iron Man.
The team was slated to appear on the second season of the Surfer's cartoon, but since it was cancelled, it could never happen. They would have appeared in a three parter when the Surfer returned to Earth.
This page is a part of DRG4's Marvel Cartoon Pages:
Featuring Spider-Man, X-Men, Fantastic Four, Iron Man, Incredible Hulk, and the Silver Surfer.