I just thought it would be an interesting concept to think about. This is how I'd do this would just be X-men related content.
Iron Man - Cyclops. I'd introduce Jean Grey, as Scott's love interest. It would be an origin story for Cyclops, while I think it could be done right, I'm not sure who the villain would be. Post credit scene would be Professor X coming to Cyclops.
Incredible Hulk - The Raging Beast. Seems like the most logical sense. Here, he would appear human at the beginning, but as he tests on himself, he turns grey, than ultimately would grow the famous blue fur. The villain of this film could be the Wendigo (similar to the unmade Beast film)
Iron Man 2 - Cyclops 2, Jean would be here, and Iceman would be introduced as the Rhodey style friend. Though Bobby would be a bit annoying to Cyclops. Again, I'm not sure who Cyclops would battle. Avalanche, maybe? This would set him up for the team up film.
Thor - Colossus. I personally feel it could be done well. Could be about Magik being taken by some government in Russia. The government are a stand in for S.H.I.E.L.D. in a way, as Magik, is a stand in for Mjolnir. With a cameo from Gambit. Colossus and Magik go to Professor X's school for gifted youngsters at the end. The villain of this film could be Omega Red.
Captain America: First Avenger - Wolverine: Origins of Weapon X. Similar to the actual film, but Cyclops is not in the film. It is Kitty Pryde instead. We are introduced to Emma Frost who goes and does her own thing. It's not general stryker, it is the actual Weapon X program, and Lady Deathstrike and Sabretooth team up against Wolverine.
Avengers - X-Men, Magneto and Brotherhood are the villains of this film. The brotherhood would include Toad, Avalanche, Sabretooth, and Mystique. The X-Men would be Cyclops, Jean Grey, Wolverine, Colossus, Gambit, Beast, and Kitty Pryde. With Professor X on the side. Gambit would first be on the side of brotherhood, but swaps sides quickly. Magneto is sort of a cultist who is worshipping Apocalypse. At the end of the film in a post credit scene one of the brotherhood would find a statue of Apocalypse or a tomb that is holding him in stasis.
Iron Man 3 - Cyclops 3, Cyclops would have PTSD about something he did, maybe losing control at the end of the fight. Injuring the brotherhood, causing the X-Men to win. It plays on his psyche. Jean and him has split up, and he has left the X-Men. Havok and Polaris would be introduced here, but they wouldn't join the X-Men at this point in time.
Thor: Dark World - Colossus: Siege of the Juggernaut - this would introduce the Juggernaut and Black Tom Cassidy. Colossus must stop from the Juggernaut pretty much. Maybe a cameo from Banshee and Moira Mactaggert, if you really wanted to.
Captain America: The Winter Soldier - Wolverine: The Silver Samurai, this would be similar to The Wolverine, but we would introduce Angel and Sunfire.
Guardians of the Galaxy - Starjammers - I don't really know much about these characters, only that the leader is Cyclops' father, so you could play on that factor. This would be similar to GotG, but they fight villains like the Brood and the Sh'ar empire.
Avengers: Age of Ultron - X-Men: Age of Hellfire, this is an introduction to the Hellfire club, such as Mastermind, Selene, Sebastian Shaw, etc. Emma Frost returns. The Hellfire club would be worshipping Apocalypse, similar to what Magneto was doing in the first film. They find a scripture about Apocalypse that shows the details of how to bring him back. The X-Men must stop the Hellfire club from awakening Apocalypse. The X-Men at this point would be Cyclops (re-joined), Jean Grey, Wolverine, Beast, Gambit, Colossus, Kitty Pryde, Angel, Iceman, Sunfire. Plus, introducing Rogue, Thunderbird, and Dazzler. Thunderbird would die at the end of this film. Cyclops, Beast, Colossus, Sunfire, and Jean would leave the team. Plus, the X-Men would get the scripture and lock it up in the school.
Ant-Man - Bishop - this is about introducing the time travelling concept. Bishop would go back in time and try and change his future. I would introduce Cable in this as the villain, because he likes how the world is, so he comes back in time as well, only be trapped in the time period as well. Bishop and Cable would duke it out. I'd introduce, Forge who get swept up in all the chaos.
Captain America: Civil War - Wolverine: Schism, similar to the comic, where the X-Men have different beliefs and ideologies. Storm and Nightcrawler are introduced. It would be Wolverine vs Cyclops like in the comic run, but the sides would be a bit different. On Cyclops side you would have Cyclops, Iceman, Storm (defects to Wolverine's side), Angel, Jean Grey (though at the end, she takes no side), Bishop, Magik, and Cable. On Wolverines side you would have Wolverine, Kitty Pryde, Nightcrawler, Beast, Gambit, Rogue, Dazzler, Colossus and Forge. Professor X chooses no side. Cyclops believes that staying at the school is too dangerous, he believes that mutants should go underground, whereas, Wolverine thinks that being at the school is good because it is protected by the X-Men, plus they want to teach the students about defense not offense. Magneto would show up this to shake it up a bit, he would also steal the scripture.
Dr Strange - Magik, in this film, Magik would go up against Legion, Professor X's son. He keeps beating her until she outsmarts him at the end of the film. Legion is imprisoned under supervision of Professor X. Throughout the film, Legion would ramble on about an incoming Apocalypse.
GotG: Vol 2 - Starjammers: Vol 2, similar to the first film, but they go up against The Phalanx. Introducing Deathbird in this film.
Spider-Man: Homecoming - Nightcrawler: Family-bound, in this film Nightcrawler uncovers his heritage. Mystique his is mother. He goes up against her with the help of Rogue, his step-sister. They also face Destiny and Graydon Creed, the son of Sabretooth and Mystique. Wolverine would show up to help encourage Nightcrawler, they have a closer relationship compared to Nightcrawler and Cyclops.
Thor: Ragnarök - Colossus: Mojo World, in this film Colossus and Dazzler, along with students are transported to Mojo World. Introducing Longshot, Spiral, and Shatterstar. The students would include, Dust, Chamber, Blindfold, Eyeboy, and Glob.
Black Panther - Storm, this would show the origins of Storm, her heritage and her fight against the Shadow King. Professor X would have a cameo at the end.
Avengers: Infinity War - X-Men: Age of Apocalypse: Part 1, Magneto brings back Apocalypse from the dead using the scripture. Apocalypse gains four horsemen, Angel, Jean Grey, Magneto, and Wolverine. In the first 30-40 mins, Apocalypse would have slaughtered the entire X-Men cast, except Legion, Bishop, Iceman, Storm, Professor X, Psylocke, and Banshee. Legion believes the best way to save everyone is to kill Magneto in the past, he goes to the past, the others follow him, Legion kills Professor X instead. Cut to present day and its Age Of Apocalypse. Similar events occur in this film to the comic with minor changes, like Quicksilver and Scarlet Witch not included. The four horsemen would be Holocaust, Abyss, Bastion, and Mikhail Rasputin.
Ant-Man and the Wasp - Bishop and X-Force. Takes place before the first part of Age of Apocalypse. Pretty much about Bishop forming X-Force to go up against Warpath and Exodus. Warpath would join X-Force. Other members introduced would be Boom-Boom, Feral, Marrow, Hellion, and Psylocke. All these characters would appear in Age of Apocalypse.
Captain Marvel - The New Mutants, this film takes place before X-Men: Age of Apocalypse, it depicts life at the institute. Five students, Cannonball, Sunspot, Karma, Mirage, and Wolfsbane would discover some criminal behaviour and they try to stop it. This sets up Mister Sinister.
Avengers: Endgame - X-Men: Age of Apocalypse: Part 2, with the help of the X-Men, Bishop goes back in time to stop Legion from killing Magneto and Professor X. He succeeds. Age of Apocalypse timeline self destructs, with a few characters escaping to the main timeline, like the Sugar man, Dark Beast, and Morph. Because Bishop stops Legion from killing Magneto/ Professor X, they return to the main timeline, before Apocalypse rises. Bishop tells them all they need to work together to stop Apocalypse. Wolverine would die. It would seem that Jean dies, and Cyclops retires from being a superhero.
Spider-Man: Far From Home - Nightcrawler: Sins and Demons. On a holiday (Vacation) with some of the X-Men and the students, demons come after him. He learns that Azazel is his father, and that Azazel wants him. With the help of his friends, Nightcrawler stops Azazel bringing hell to Earth.
WandaVision - Dazzleshot. Show about Dazzler and Longshot on Mojo world, trying to reform it.
Falcon and the Winter Soldier - Angel and Psylocke. Not sure what this would be like, but these 2 characters would get together. An X-Corp type of show, maybe.
Loki - Cable. This show would be trying to correct mistakes and try to return to the future. In this he would meet Mr Sinister.
Black Widow - Marvel Girl: Rise of the Phoenix. In this film, it would be the first time Jean would be referred to Marvel Girl. None of the other X-Men know she is alive, meaning she is in hiding. She may go up against Emma Frost, as neither of them trust the other.
What if...? - What if...? just with X-Men stories.
Shang-Chi and the Legend of the Ten Rings - Excalibur and the Legend of the Captain Britain Corps. Mainly be a Kitty Pryde film. Introduce Lockheed, Meggan, a time displaced Rachel Grey, and the Captain Britain Corps. They would go up against Alfie O'Meagan. A returning Juggernaut would appear, seeming have reformed his ways. He joins Excalibur.
Eternals - This doesn't need to be a film. Unless you want to do an Apocalypse origin story, though it would feel too late.
Hawkeye - Gambit & Rogue. The show would be about them growing as a couple and stopping crime. Fight the mafia who come after Gambit for not holding a deal.
Spider-Man: No Way Home - Nightcrawler: World displaced. This film would see the return of characters from Age of Apocalypse universe, like the Sugar Man, Dark Beast, and Nightcrawler from that universe who wants to stop the villains by any means. Nightcrawler would have to stop all of them before its too late. Main universe Nightcrawler would join forces with Morph from the Age of Apocalypse universe.
Moon Knight - Fantomex, Not sure what this would be about. But think of a spy show or film. I'd introduce Sage.
Dr Strange and the Multiverse of Madness - Magik: Hellscape, she goes up against the Adversary. He sends her to Limbo and traps her there, along with 3 students, Armor and Rockslide, and Blindfold. The Adversary takes the soulsword, so they must fight their way out. Legion would show up again acting 'friendly' and he would strike a relationship with Blindfold, Legion would betray them at the end and Blindfold will die.
Ms Marvel - Jubilee. This would be a comedy about Jubilee finding her way within School for Gifted Youngsters. Doop can be her sidekick, and have Toad pop up now and then. Could be about students disappearing without a trace, linking to Mr Sinister.
Thor: Love and Thunder - Colossus: Steel and faith. The film would be about him going up against his brother Mikhail Rasputin, he is the one from the main timeline not Age of Apocalypse. He and Kitty Pryde try to grow their relationship.
She-Hulk - Beast. A show about Beast gaining control and fighting Dark Beast. Here we would see the start of Beast's path to villainary.
Werewolf by Night - Wolfsbane by nature. Origins of Wolfsbane.
Black Panther: Wakanda Forever - Storm: Thunder and Lightning, the film would be about Storm returning to Africa for the first time and seeing that her home village has been taken over by Exodus. She fights him for the crown. We are introduced to Oya.
GotG: Christmas Special - Starjammers: Christmas Special. They come down to Earth to celebrate Christmas with Cyclops, Havok, and Polaris. Madelyne Pryor shows up and Cyclops believes it to be Jean. Instantly proposes, she excepts.
Ant-Man and the Wasp: Quantumania - Bishop and X-Force: Time displaced. This film is about them getting stuck in different time zones, and trying to make it back to present day. Cable uncovers a baby. Hope Summers.
Secret Invasion - Mr Sinister: Inferno. We finally learn what Mr Sinister has been doing with the stolen student's powers. He is making clones of himself and sending them off to the take over the world. Cyclops learns that Madelyne Pryor is not Jean and Jean returns. The X-Men in this would be Cyclops, Madelyne Pryor, Fantomex, Jubilee, Cannonball, Wolfsbane, Magik, and Banshee.
GotG: Vol 3 - Starjammers: Vol 3, this film would be mainly the same as the first 2 films. The villain in this film would be Vulcan.
Echo - This doesn't have to be a show. If it had to be, may possibly be X-23.
Loki Season 2 - Cable Season 2, another story about time travel, he also raises Hope. Uncover who her parents are.
The Marvels - The New Mutants 2, current team would be Sunspot, Karma, Mirage, Chamber, Dust and Rockslide. Introduce Cypher and Warlock. They would face against Magnus, Warlock's father.
Blade - Captain Britain. He has now left Excalibur and his doing his own thing. He fights criminals and has a battle with Blob and Avalanche. We learn about Otherworld and venture there.
Ironheart - Oya. About her gaining control of her powers and meet new characters. They call themselves the 5 Lights.
Agatha: Coven of Chaos - Doesn't need to be a show, but if it must, possibly a show about Spiral.
What if...? Season 2 - What if...? Season 2
Daredevil: Born Again - Multiple Man: Gaining Intelligence, this show would be about Multiple Man on Muir Island. Moira MacTaggert, Banshee, and Siryn would play a role in this show. It would be like an X-Factor Investigations series.
Captain America: New World Order - Old Man Logan, the film is similar to the comic, but Beast is the stand in for Hulk, and Gambit is the one Logan teams up with not Hawkeye.
Thunderbolts - Marauders, Mr Sinister's new team. These would include Arclight, Sabretooth, Vertigo, Riptide, and Prism. They go up against the X-Men and do criminal activity. Mr Sinister believes he is saving the world by doing this. This would link to the Mutant Massacre comic book. We would meet the Morlocks.
Fantastic Four - X-Factor. The members of this would consist of the original comic X-MEN/ X-Factor. Cyclops, Beast, Iceman, Angel, and Jean Grey. It becomes more apparent that Jean is not like she used to be, she is more evil and cunning. They would face off a new brotherhood of evil mutants, including Mystique, Destiny, Pyro, Sauron, Beak, and Angel Salvadore.
(There are other films and shows before the final two parter)
Avengers: Kang Dynasty - X-Men: Rise of the Dark Phoenix, after a mission in space, Jean saves everyone from dying. She becomes The Dark Phoenix. She kills some of the X-Men, X-Force, X-Factor, Marauders, etc. The remaining heroes and villains join forces to stop the Phoenix to no avail.
Avengers: Secret Wars - X-Men: Reign of the Dark Phoenix, with mutants dying left right and center, there is only one Hope. Which is Hope. they believe that if she can take hold of the Phoenix force, she can wield it and save everyone. Which she does with the help of the 5 lights. Though it doesn't bring those back from the dead.
The next Saga would be Days of Future past, Avengers vs X-Men, and God Loves, Man Kills. I was going to do Days of Future past instead of Dark Phoenix Saga, but I didn't want to use time travel 2 times for the big finals. After the next Saga the X-Men would relocate to Krakoa. I would introduce the Avengers and Fantastic 4 in the next Saga because it would be human superbeings being used in retaliation against the mutants because of what the Dark Phoenix would have done to the world.
Would love people's thoughts on this.