A third idea is a cross - over where a common enemy forces the two groups to work together. The Avengers are used to big - scale threats, and the OHSHC members are not fighters in the traditional sense. But the OHSHC boys could use their wealth and influence to provide resources for the Avengers. Haruhi, on the other hand, could offer a different perspective on problem - solving, which might help the Avengers in unexpected ways.
Another possibility is that the Avengers end up in the OHSHC world. The Avengers would be really out of place in that high - school - like setting. Thor might be really confused by all the tea parties and formalities, while Iron Man would probably try to find a way to use the technology there, which is much less advanced than his own. Black Widow could blend in a bit better, using her espionage skills to navigate the social hierarchies of the OHSHC club.
Perhaps Goku lands in New York City and his power level is sensed by the Avengers. Iron Man is initially skeptical but Captain America is more open - minded. They test Goku's abilities and find out he can move at incredible speeds and has near - invincible defenses. So they ask him to train the Avengers in new combat techniques, which leads to some humorous and action - packed training sessions.
A possible fanfiction could involve a crossover where some of the Avengers are sent to Camp Half - Blood. Imagine Tony Stark trying to figure out how the magic at the camp works while also being highly amused by the whole concept of demigods. Steve Rogers could bond with some of the more heroic demigods over their shared sense of duty. Meanwhile, Percy and his friends have to keep an eye on the Avengers to make sure they don't accidentally disrupt the delicate balance of the camp. And then, they all have to face a threat that targets both the Avengers and the demigods, like a group of villains who want to steal the powers of both.
Maybe in the fanfiction, the Avengers need someone with John Wick's particular set of skills for a stealth mission. John Wick initially refuses but is later convinced when he realizes the threat is global. During the mission, they learn from each other's combat styles and strategies, and John Wick's no - nonsense attitude impresses the Avengers.
One idea could be that Naruto is somehow transported to the Marvel universe where the Avengers are. He could use his ninja skills, like his shadow clone jutsu, to confuse the villains that the Avengers are facing. Maybe he teams up with Iron Man and they combine their tech and ninjutsu to create some really cool weapons or defenses.
A fanfiction could involve a crossover where the Avengers are shrunk down to the size of the Gems in Steven Universe. They have to adapt to this new world and its rules. For example, they might have to learn how to use Gem weapons and powers. In return, they could teach the Gems about human combat techniques that are different from what the Gems are used to. This would create a lot of humorous and action - packed situations.
One idea could be that Batman, in his quest to fight crime in Gotham, discovers some sort of interdimensional rift that leads him to the world of The Avengers. He then has to team up with them to stop a common enemy that is using technology from both universes to cause chaos. For example, Loki could be teaming up with some of Batman's rogues gallery like The Riddler to create complex puzzles and illusions that are both magical and technological in nature.
In a fanfiction, the Akumas from Miraculous Ladybug could start to appear in the Avengers' world. The Avengers are initially confused by these strange creatures but quickly realize they need to work with Ladybug and Cat Noir to stop Hawk Moth, who has found a way to cross dimensions. The combined forces would make for an exciting story, with each character bringing their unique abilities to the fight.
One idea could be that Loki gets turned into a vampire while in the midst of his schemes against the Avengers. This new state gives him different powers and motives. He might struggle with his newfound thirst and also use his vampire abilities to outwit the Avengers in different ways.
One idea could be a crossover where Hydra discovers the wizarding world in the Harry Potter universe and tries to use magic for their evil purposes. The Avengers somehow get wind of this and team up with Harry Potter and his friends to stop Hydra. Maybe they have to battle magical creatures that Hydra has corrupted with dark magic.
One idea could be that Harry Potter, as an Animagus, somehow gets transported to the Marvel universe. He could team up with the Avengers in his animal form, perhaps using his unique abilities to gather intelligence. For example, as a stag, he could move quickly and unnoticed in certain terrains, providing valuable information to the Avengers before a battle.