A great Disney Frozen crossover fanfiction idea is to have Elsa and Anna meet the characters from Moana. Elsa's power over ice could interact with Moana's connection to the ocean in interesting ways. Maybe they need to combine their powers to stop some kind of natural disaster. Or, consider a crossover with Cinderella. Cinderella could visit Arendelle and teach Anna some courtly manners while Anna shows Cinderella the fun of sledging on ice.
One idea could be that Elsa accidentally travels to another Disney world like Aladdin's Agrabah. There, she could use her ice powers in the desert, creating ice sculptures that amaze the locals. Another could be a crossover with The Little Mermaid. Maybe Ariel discovers an iceberg with Elsa trapped inside and helps her get free. They could then explore each other's worlds together.
A crossover with Moana might be interesting too. Moana could take Elsa and Anna on a journey across the ocean in her boat. Elsa could use her ice powers to create paths or structures on the water. They could face challenges like sea monsters and learn from each other's different ways of life.
One interesting idea could be a crossover with "Moana". Elsa's ice powers and Moana's connection to the ocean could create a really cool dynamic. Maybe Elsa accidentally freezes part of Moana's ocean and they have to work together to fix it. Another could be with "Tangled". Rapunzel's long hair and her adventurous spirit combined with Elsa and Anna's journey in Frozen 2 would be exciting. Rapunzel could use her hair to help them climb mountains or cross chasms. A third idea is a crossover with "Beauty and the Beast". Belle's love for books and knowledge could help Elsa understand more about her powers and the history of magic in the Frozen world.
There could be a fanfiction where Loki, the trickster from the Avengers, ends up in Arendelle and causes chaos. He could manipulate some of the characters or try to steal Elsa's powers for his own gain. And on the other side, the Avengers are searching for him. Meanwhile, the Frozen characters have to deal with Loki's mischief on their own until the Avengers arrive. This would create a lot of interesting scenarios and character interactions.
One idea could be that Elsa, with her ice powers, is mistaken for a powerful ice mage in Skyrim. The Dragonborn might seek her out to learn more about controlling ice magic in a different way. Another could be that the Frozen characters end up in Skyrim during a particularly harsh winter and have to adapt to the more dangerous environment. They could encounter bandits or wild animals, and the Skyrim characters could help them survive.
One idea could be a crossover between characters from different Disney Infinity franchises in a post - apocalyptic world. For example, Jack Sparrow from Pirates of the Caribbean and Elsa from Frozen teaming up to find a way to restore their shattered universes. Another idea is to have Buzz Lightyear and Stitch on an intergalactic adventure where they have to stop an evil force that is threatening multiple Disney worlds.
One idea could be that Goku ends up in the world of Aladdin. He might mistake the flying carpet for a new kind of Ki - powered vehicle. And he could use his martial arts skills to help Aladdin fight off Jafar's minions in a really action - packed way.
One idea could be having Maleficent and Ursula team up. Maleficent could use her dark magic to help Ursula get more powerful in the ocean realm. Maybe they plot to take over both the land and the sea. They could start by causing chaos in the kingdoms near the shore, like making storms and scaring the fishermen.
One idea could be that the Avengers get transported to a Disney fairy - tale world. For example, they end up in Arendelle from 'Frozen'. Iron Man could try to figure out how to adapt his suit to the cold, while Captain America tries to lead the way through the icy terrain. Thor might find similarities between the magic in Arendelle and Asgardian magic.
One idea could be that Tarzan, while exploring the jungle, stumbles upon a strange icy portal which transports him to the world of Frozen. He meets Elsa and is amazed by her ice powers. Tarzan, with his jungle skills, could help Elsa understand the natural world in a different way. Maybe he shows her how animals communicate and live in harmony in the jungle, which in turn gives Elsa new ideas about how to interact with the spirits in her own world.
One idea could be that Elsa's powers are mistaken for some sort of new super - weapon by the villains in the Avengers universe. So, the Avengers have to figure out if she's a threat or an ally. Another could be that the Avengers get trapped in Arendelle during a mission and have to work with the Frozen characters to get back home. Maybe Thor could teach Kristoff some combat skills while Elsa helps Iron Man with his suit's temperature control system.