One interesting crossover could be the combination of magic from 'Harry Potter' and the superpowers in 'Sky High'. For example, a character from 'Harry Potter' might attend Sky High and have to figure out how to use their wand magic in a school full of superpowered individuals. Maybe Hermione would befriend some of the brainiac superpowered students and they'd exchange knowledge about different types of magic and powers.
In 'Harry Potter and Sky High fanfiction', a crossover might involve the Quidditch players from 'Harry Potter' competing against Sky High students in a flying race. The different flying techniques and abilities would make for an exciting story. The Firebolt broomsticks against the super - powered flight of Sky High students would be a sight to behold.
Well, a great crossover idea in the fanfiction might be a Quidditch match between Monster High and Hogwarts students. The Monster High ghouls and guys would bring their unique abilities to the game. Also, a plot where the Hogwarts teachers have to deal with the more monstrous behavior of Monster High characters, like Frankie Stein's electrical outbursts during a Potions class, could be really fun.
One interesting crossover could be the characters from High School Musical attending Hogwarts. They might be sorted into different houses and have to deal with magic classes while still having their love for musical performance. For example, Troy could be a Gryffindor and use his charm and leadership skills in Quidditch.
Well, in some fanfiction, we might see Anna and Kristoff visiting Hogwarts. They could be amazed by the moving staircases and magical creatures. In reverse, Harry, Ron and Hermione could end up in Arendelle. Hermione might be intrigued by the way Elsa controls her ice powers and try to find a scientific or magical explanation for it. Also, the Dementors from Harry Potter could be compared to the dark forces in Frozen 2, like the mist that Elsa has to face.
One interesting crossover could be the use of magic in the Avengers world. For example, Hermione could use her knowledge of spells to help the Avengers solve a problem that technology couldn't. Maybe she could use a spell to break through an impenetrable force field created by an enemy. Another aspect could be the Avengers characters learning magic. Tony Stark might be fascinated by the concept of magic and try to incorporate it into his technology. Or Thor could share his knowledge of Asgardian magic with the Hogwarts students.
One interesting crossover could be a scenario where Hermione uses her magic to help Elsa control her powers better. Maybe she creates a spell that can soothe Elsa when she's about to lose control.
In some fanfiction, Maleficent might team up with a dark wizard from the Harry Potter universe. They could combine their powers to try and take over both the wizarding world and the fairy - tale land where Maleficent comes from. This would create a complex power struggle with the heroes having to find new ways to combat them.
One interesting crossover could be the characters from Harry Potter visiting Narnia. For example, Harry, Ron, and Hermione might find themselves in Narnia through some magical accident. They could then interact with the talking animals and magical beings there, like how they interact with the magical creatures in their own wizarding world. Maybe they would help the Narnians in a battle, using their unique Hogwarts - taught magic.
One interesting crossover could be the use of spells. For example, a Charmed one might learn a spell from the Harry Potter world like the Patronus charm. It could be used in a new and different way in the Charmed universe, perhaps to fight a new type of demon that is vulnerable to positive magic like a Patronus.
One interesting crossover could be Superman visiting Hogwarts. He might be amazed by the magic there. Maybe he tries to learn some spells, but his superpowers interfere. For example, when he tries to use a levitation charm, his super strength makes the object fly out of control.
One interesting crossover could be a scenario where Harry Potter and his friends encounter Janemba's chaotic powers in the wizarding world. Maybe Janemba's otherworldly abilities disrupt the magic there, and Harry has to use his knowledge of both magic and the strange new power he's facing to set things right. For example, he might combine spells with his natural courage to combat Janemba's minions.