One idea could be a St Trinians crossover with Sherlock Holmes. The girls of St Trinians could get involved in a mystery that Sherlock is also investigating. Their unorthodox ways might both amuse and frustrate the great detective.
A crossover with James Bond could be great. Having a St Trinians girl as a Bond - girl - like character, but with her own unique St Trinians twist. She could outwit the villains in ways Bond never expected.
One idea could be a Harry Potter and Sherlock Holmes crossover. Imagine Sherlock using his deductive skills to solve the mysteries in the wizarding world. Another could be a crossover with the Hunger Games. The wizards could be forced into the arena, and they'd use magic in unexpected ways to survive. A third one might be a crossover with Alice in Wonderland, where the topsy - turvy world of Wonderland intersects with the magical world of Harry Potter.
A Naruto and Medusa fanfiction could be really interesting. It might involve Naruto being transported to a world where Medusa exists. Maybe Naruto's ninja skills would be put to the test against Medusa's petrifying gaze. He could use his shadow clone jutsu to confuse her and then find a way to defeat her without looking directly at her.
The crossover could start with a strange portal opening between the two worlds. Naruto characters like Sasuke might be intrigued by the bending abilities in the Avatar world. He could try to learn firebending, thinking it could enhance his own fire - based jutsu. And the Avatar characters could be equally fascinated by ninjutsu.
One idea could be that Greninja, being a ninja - like Pokémon, somehow gets transported to the Naruto universe. It could team up with Naruto and use its water - based attacks in combination with Naruto's Rasengan. Maybe Greninja's ability to blend into the shadows could be used in stealth missions in the Hidden Leaf Village.
One idea could be a crossover with the Dragon Ball Super universe and the DC Comics universe. Zamasu could team up with Darkseid, believing they share a similar view of bringing 'order' to their respective realms. Another idea is a crossover with the Naruto universe, where Zamasu tries to impose his will on the ninja world, facing off against powerful shinobi like Naruto and Sasuke. Or perhaps a crossover with the Star Wars universe, with Zamasu as a Sith - like figure, trying to gain control over the Force.
One idea could be that the turtles from 2012 somehow get transported to the 2018 universe. They could be really confused by the different art styles and the new gadgets the 2018 turtles have. The 2018 turtles, on the other hand, would be intrigued by the more traditional look of the 2012 turtles. This could lead to some funny moments as they try to communicate and figure out how to get the 2012 turtles back to their own universe.
One idea could be a Vampyr and The Witcher crossover. The main character from Vampyr could find himself in the world of The Witcher, facing different monsters and having to adapt to the new magic system there. He might encounter Geralt and they could either team up or be at odds due to their different views on handling supernatural beings.
One idea could be a Moana crossover with Frozen. Moana could end up in Arendelle due to a magical storm. She teams up with Elsa and Anna to stop an approaching iceberg that is threatening both her island and Arendelle. Moana's skills in sailing and her connection with the ocean could be combined with Elsa's ice powers to find a solution.
The plot could involve Hermione trying to reform the St Trinians' school. She sees all the chaos and unruliness there and decides to use her Gryffindor courage and Ravenclaw intelligence to bring some order. Along the way, she has to deal with the unique personalities of the St Trinians girls, who are not used to the strict Hogwarts - like discipline she tries to introduce.