Mojovision - S2-E11
Trivia: When the camera is panning across Mojo's studio audience after he has abducted the X-Men, you can see an older man in the middle of the crowd. This man is a caricature of Marvel Comics legend Jack Kirby. Coincidentally, Kirby died the day after this episode originally aired. (00:07:52)
Phaneron
Trivia: A few weeks into the show's production, the staff was informed by Marvel that their character designs had to be changed. This is because the characters were modelled on artist Jim Lee's redesigns in the comics, and he, along with some other artists, were in the process of leaving Marvel Comics to found Image Comics. To convince Marvel to change their minds, storyboard artist Will Meugniot submitted a deliberately awful looking model sheet that looked reminiscent of 1970s Hanna-Barbera cartoons.
Phaneron
Days of Future Past: Part 1 - S1-E11
Trivia: After Bishop travels into the past, he hears one kid telling another that they will be playing the new Punisher game "Assassin." When the Punisher was first being developed, he was originally going to be called The Assassin.
Trivia: At the end of the opening titles, there is a short bald man in a green outfit running with Magneto's crew. For years, fans had wondered who this character was, as he has no counterpart in the comics, and he only had a fleeting appearance in the season 1 episode "Slave Island." Series director Larry Houston finally revealed that the character is nobody in particular, and that he was mistakenly placed in the opening titles by the animation company AKOM.
Phaneron

One Man's Worth: Part 1 - S4-E1
Trivia: The man that aids Wolverine in the coffee shop is Johnny Strabler, Marlon Brando's character from the film "The Wild One." (00:16:45)
Phaneron

The Juggernaut Returns - S3-E17
Trivia: When the new Juggernaut crashes through the film studio, the production being filmed is a parody of Mighty Morphin' Power Rangers. There is even a short musical phrase similar to MMPR's theme song. (00:16:10)
Phaneron
Trivia: This episode depicted Bella Donna as being Gambit's former fiancée. In the comics, the two were actually married. This change was likely made for the show due to it being too mature of a theme for a kids' show for Gambit to have both an estranged wife and an extramarital relationship with Rogue.
Phaneron
Mojovision - S2-E11
Trivia: The robot that attacks Jean Grey is a replica of the Punisher. (00:16:05)
Trivia: When Wolverine is explaining Omega Red's back-story to Colossus, a picture of Captain America is briefly visible. This is a nod to the comic books, where Omega Red was the Soviet Union's attempt to create their own super soldier similar to Captain America. (00:14:05)
Phaneron

Trivia: One of the images in Gambit's mind-scan is of fellow Marvel Comics superhero Ghost Rider. (00:07:45)
Phaneron
The Dark Phoenix (2): The Inner Circle - S3-E12
Trivia: The main antagonists in this episode as well as the episode that follows it are the Inner Circle. In the comics, the Inner Circle are a sort of clandestine group of mutants that operate within an elitist social group known as the Hellfire Club. Due to censorship reasons, the Hellfire Club aspect of the group is not acknowledged. Its members are visually based on famous actors. Sebastian Shaw is based on Robert Shaw, Harry Leland is based on Orson Welles, Donald Pierce is based on Donald Sutherland, and Mastermind in his Jason Wyngarde persona is based on Peter Wyngarde. The White Queen/Emma Frost is based on the character Emma Peel from the British television series "The Avengers."
Phaneron
Trivia: Following Disney's acquisition of Fox, the creators of this show pitched a revival, which would presumably stream on Disney+. It remains to be seen if anything comes of it. Producer Larry Houston has said he would come out of retirement specifically to work on this.
Phaneron
Suggested correction: How is it trivia that a show has been pitched, but not produced or even confirmed?
This is a highly popular show and the creators have shown interest in a continuation of it. Just because it hasn't been confirmed doesn't mean people won't find the idea interesting.
Phaneron
Trivia: Chris Potter, who voiced Gambit, has said he always wanted to play Gambit in the films, stating that he looked like Gambit when he was younger. He was actually brought in to audition for the role of Cyclops for the first X-Men film, but thought to himself before the audition that he didn't want to play Cyclops and have to wear those "bad sunglasses."
Phaneron