One idea could be to cross 'Every Witch Way' with 'Charmed'. The witches from 'Every Witch Way' could visit the Halliwell Manor and learn some new spells from the Charmed Ones. Maybe they could work together to defeat a powerful dark force that threatens both their worlds.
A crossover with 'Charmed' would also be great. The three Halliwell sisters and Sabrina could team up to fight a powerful dark force. They could exchange magical knowledge and learn from each other's different approaches to magic.
One interesting idea could be that Naruto somehow gets transported to Sabrina's world. He could use his ninja skills in the magical world of Greendale. For example, his speed and stealth could be useful in the spooky forests around Sabrina's town. Another idea is that Sabrina uses her magic to help Naruto in his battles in the Naruto universe. Maybe she could use her magic to heal some of his injured friends or to create illusions to deceive his enemies.
One idea could be a crossover with another Disney adventure movie like 'Pirates of the Caribbean'. The characters from 'Race to Witch Mountain' could end up on a pirate ship while trying to escape some new threat related to their original mission. Maybe the aliens from Witch Mountain have some sort of power that the pirates are after.
A more complex scenario could involve a group of witches who are at war in their own realm. They decide to bring some of the powerful Naruto characters into their world to fight on their behalf. Naruto and his friends would have to adapt to the strange magic - filled environment and the political intrigue of the witches' war.
An interesting plot could be that Emma loses her memory and Daniel has to make her fall in love with him all over again. He takes her to all the places that are special to them, tells her stories of their past adventures. But there's also a dark force that doesn't want Emma to remember, and Daniel has to protect her from it while trying to re - kindle their love.
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.
A Thundercats and Star Wars crossover fanfiction would be really cool. The Thundercats could be in the Star Wars universe, and their unique powers and weapons could be a great addition. Maybe the Thundercats could help the Jedi or the Rebels in their fight against the Sith or the Empire. For instance, Cheetara's speed could be useful in battles, and Tygra's illusions could be used to deceive the enemy.
One idea could be a witch who uses her powers to save a small village from a mysterious dark force that has been causing disasters. Another could be a story about a young witch trying to fit into a non - magical world while still maintaining her magical identity. Maybe a fanfiction where a group of witches from different covens come together to fight a common enemy like an ancient evil wizard.
If it was a crossover with 'The Vampire Diaries', Bonnie Bennett would be an interesting character to include. As a powerful witch in her own right, she could collaborate with the witches from 'Every Witch Way' to fight against any supernatural threats that emerge. Also, Damon Salvatore could add some drama and conflict, especially if he has an interest in one of the 'Every Witch Way' witches.
One idea could be that Scarlet Witch accidentally transports herself into the Harry Potter universe. Maybe she uses her powers to help the students at Hogwarts learn about different forms of magic from her world. For example, she could show them how to manipulate reality on a small scale, which is something very different from the magic in the Harry Potter series.