Obviously, had the 1989 "Pryde of the X-Men" pilot extended beyond that (and the Konami arcade game):
1x02: Escape the Savage Land!
Professor X and his X-Men are baffled to discover a tropical jungle in the middle of Antarctica. There they meet Ka-Zar, a brave warrior who helps them fight off a group of monsters that stalk our heroes. Things get even stranger when Magneto suddenly appears
1x03: One Nation, Under Nefaria
Count Nefaria traps the entire city of Washington, D.C. beneath a giant dome that not even the military's forces can penetrate. Then he makes his team of X-Men imposters look responsible for the deed. Can the real X-Men clear their names and free the US capital before its too late?
1x04: Not by a Longshot
Cerebro detects a new mutant in the city. When the X-Men meet up with him, they find out hes an amnesiac and doesnt remember anything about his past, or his abilities. The team is in awe of his apparent streak of good luck, but so is Magneto
1x05: And Your Enemies Closer
When a mad scientist named Dr. William Stryker kidnaps Professor X and wires him up to a machine that will use his psychic energy to destroy all mutants across the world, the team turns to the only person thats powerful enough to stop it from happening: Magneto.
1x06: Island of Fear
After the X-Men answer a distress call from their friend Banshee in Scotland, they travel across the globe to his island laboratory and find it in shambles. A monstrous experiment of his is on the loose, and it lurks in the dark, watching the team
1x07: Flight of the Dark Phoenix, Pt. 1
Jean Grey, a former member of the X-Men who disappeared after a fateful mission in outer space, finally returns to the mansion. Cyclops is beside himself. Is she what she seems? But while the rest of the team explain her history to Kitty, the White Queen plots to harness Jean's psychic powers for her own use. Meanwhile, a group of aliens appear on earth, searching for something called the Phoenix.
1x08: Flight of the Dark Phoenix, Pt 2
Despite the White Queens attempts to control Jean Greys mind, the powerful Phoenix entity wont allow it. But everyone is shocked when the mysterious extraterrestrials put Jean Grey on cosmic trial for destroying their entire home planet! Can the X-Men stop this madness, or will the Phoenix powers be the end of Jean Grey?
1x09: The Weapon X-periment
When the Danger Room malfunctions during training, Kitty Pryde and Wolverine are stuck inside one of its simulations. While the rest of the team try to fix the problem in the control room, Wolverine tells the new recruit about how he joined the X-Men and the mysterious Weapon X project.
1x10: Meet The New Mutants
When the X-Men are captured and taken off into space by strange aliens known as the Brood, its up to Kitty Pryde and a group of misfit teenage students from Xaviers School for the Gifted to save them. But the real question is: can they get along first?
1x11: The Spider-Man Adventure
Chaos ensues when Mysterio joins forces with Magneto to take over the Daily Bugle headquarters. The X-Men team up with Spider-Man and his amazing friends Firestar and Iceman once again to derail their plans, making Kitty feel like the odd one out.
1x12: The Uncanny Space Knight
When a race of alien witches known as Wraiths come to take over our planet, the team calls upon the help of their number one enemy - ROM the space knight. But Magneto seeks to reprogram him to serve his own agenda...
1x13: Back to the Present
Kitty keeps phasing in and out of the future, one thats ruled by the Brotherhood of Mutants and their army of robot sentinels - a dark future where the X-Men have lost the war and are hunted like fugitives. Can she stop this timeline from coming to pass with the help of Wolverine and Professor X?
Season 2:
2x1 - Old Friends, Pt. 1 - The Iceman Cometh - Iceman and Beast have come from Los Angeles looking for the X-Men's help. The New Defenders have been soundly beaten, and only the X-Men can help them save one of their mutual former friends... Angel.
2x2 - Old Friends Pt. 2 - On Angel's Wings - Moondragon has located Angel, but now a larger problem looms overhead... the Dragon of the Moon! Will the X-Men and New Defenders be able to even survive the upcoming battle?
2x3 - Mayhem in Murderworld - The X-Men, needing a much deserved vacation, decide to stop by a new theme park. Little do they know that master assassin Arcade has designed this park with a few twists...
2x4 - Eye of the Storm - Peter Henry Gyrich returns from Season 1's The Uncanny Space Knight, and in an experiment gone wrong, has stolen Storm's powers! Can the weather witch get her powers back with the help of new ally, Forge?
2x5 - Cry Havok - Alex Summers was a member of the X-men by the code name Havok, until he went to college. He's back, and he needs the X-Men's help in rescuing his girlfriend, former X-Men Lorna Dane, (Polaris) from a mutant called the Living Pharaoh. But can Havok keep his powers in check while fighting such a powerful foe?
2x6 - Breaking Bonds - A visiting Captain America has come to the X-Mansion wondering if Quicksilver and the Scarlet Witch should be considered for Avengers membership. Professor X recounts how the two heroes started off as enemies of the X-Men, but shifted to become allies.
2x7 - Beauty and the Beast - Dazzler is abducted in the middle of the night by Hank McCoy, the Avenger and former X-Man called Beast, with a problem only she can help solve!
2x8 - Secret Wars, Pt. 1 - The X-Men have walked through a mysterious door only to find themselves with other heroes in a battle for the ages! Can they learn to trust the other superheroes, or will they need to go their own way? Even on a different planet, they might be in a world that hates and fears their mutant gifts...
2x9 - Secret Wars, Pt. 2 - The X-Men have made peace with the other heroes and Magneto, but now must face a cosmically powered Doctor Doom. Can Professor X and Cyclops follow Captain America's lead to victory?
2x10 - Contest of Champions - Colossus has been pulled into a contest of strength and skill by the Champion, along with the Hulk, the Thing, and several others. Who will come out the victor?
2x11 - Mutant Massacre Pt. 1 - The Marauders - The X-Men, worn out from the Secret Wars and the Contest of Champions are called to rescue underground mutants from the deadliest opponents they've ever faced.
2x12 - Mutant Massacre Pt. 2 - Survival - Decimated from their losses and needing recovery, the depleted ranks of the X-Men need to accept help from Thor to defeat these new opponents. Can the group ever recover?
2x13 - Rebirth - Psylocke, Longshot, Rogue, and Havok have joined Colossus, Storm, Dazzler, and Wolverine to make an all-new team of X-Men. But with Professor X with Lilandra recovering from his injuries, and Magneto being put in charge at the Mansion, will anything ever be the same for the team? Get ready for the stage to be set for an all new team next season, as the group goes global, starting with the Australian outback!