One great example could be a crossover between 'Once Upon a Time' and 'Harry Potter'. Imagine the fairy - tale characters from 'Once Upon a Time' finding their way into the magical world of Hogwarts. Snow White could be a student in the Defense Against the Dark Arts class, learning spells alongside Harry and his friends. Another example is a crossover with 'The Lord of the Rings'. Characters like Regina might be intrigued by the power of the One Ring and get involved in the epic quest in Middle - earth.
One popular theme is the collision of different magical worlds. For example, characters from 'Once Upon a Time' might cross over into the 'Harry Potter' universe. Another theme could be the exploration of different power dynamics. Characters with different magical abilities meet and have to figure out how to co - exist or compete. And the theme of redemption through cross - over is also common. A character from one story who has made mistakes gets a chance to redeem themselves in a new, crossover setting.
First, choose the two (or more) universes you want to cross over. For example, if it's 'Once Upon a Time' and 'Pirates of the Caribbean', think about how the magic of 'Once Upon a Time' would interact with the swashbuckling world of pirates. Then, decide on a central plot. Maybe a character from 'Once Upon a Time' is accidentally transported to the Caribbean and has to find a way back home. Next, create some rules for how the different elements will combine. Like, will the fairy - tale magic work the same way in the pirate world? And start writing, introduce the characters and the initial situation clearly.
One common theme is the clash of different worlds. Stiles comes from a world with its own set of rules, and 'Once Upon a Time' has its own magical and fairytale - like rules. So, there's often a theme of adjustment and adaptation. Another theme is the discovery of new powers or abilities. Stiles might find out he has some latent magical abilities in the 'Once Upon a Time' world.
One great Teen Wolf and Once Upon a Time crossover fanfiction is 'The Lost Wolf in Storybrooke'. It combines the dark, supernatural elements of Teen Wolf with the fairytale - like world of Once Upon a Time. The story has Scott McCall finding himself mysteriously transported to Storybrooke and having to navigate the new rules and characters there. It's really exciting to see how he interacts with the likes of Emma Swan and Regina Mills.
A 'found family' trope is quite common. Characters who were alone or estranged in the show form a close - knit family in fanfiction. For instance, Henry might bring together different characters who then become his new family. Also, the 'hurt/comfort' trope, where a character is hurt (physically or emotionally) and another character comforts them, is frequently used in Once upon a Time fanfics.
In a Frozen - Once Upon a Time crossover, Elsa's cautious and self - isolating personality would be really interesting when combined with the world of Once Upon a Time. She might initially be wary of the new characters, but as she realizes they also face struggles, she could open up. Anna's eagerness to make friends and her loyalty would blend well with characters like Belle, who also values friendship. Kristoff would probably get along with the more down - to - earth characters. His no - nonsense attitude could be refreshing in the often - magical and complex world of Once Upon a Time.
One interesting plot could be that a dark force in 'Once Upon a Time' decides to use the power of the vampires and werewolves in Twilight to take over both worlds. The characters from both universes would have to team up to stop it. The heroes like Emma from 'Once Upon a Time' and Edward from Twilight would lead the charge. They would have to learn about each other's powers and weaknesses quickly to be effective.
Well, the characters from 'Once Upon a Time' are often from fairy tales and have their own set of magic and personalities. The Twilight characters are in a more modern, vampire - werewolf - human love triangle world. If they were to interact, the vampires in Twilight might be intrigued by the dark magic in 'Once Upon a Time'. For example, Edward might be curious about Regina's use of magic and how it differs from his own vampiric abilities. And the werewolves in Twilight could potentially find common ground with some of the more animal - like characters in 'Once Upon a Time'.
Well, it might be that the Avengers get transported to the Once Upon a Time universe. Thor could mistake the Evil Queen for Loki in a way, since she's so devious. And then you could have Black Widow using her spy skills to figure out the political intrigue in the fairy - tale kingdoms. The Hulk could be like a giant ogre in that world, and the heroes from Once Upon a Time would be both scared and intrigued by his power.