Well, for amphibia crossover fanfiction, you could do a crossover with "Rick and Morty". Rick could build some sort of portal device that accidentally sends Morty to Amphibia, and then he has to rescue him. Or a crossover with "Ninjago". The ninja could come to Amphibia and use their martial arts skills to help out. Another option is a crossover with "Regular Show". Mordecai and Rigby could end up in Amphibia and their lazy and comical ways would contrast with the more serious Amphibia characters.
Perhaps a story where a character reacts to the dangerous creatures in Amphibia. They initially fear them but then learn to co - exist with them. This could involve a lot of character development as they overcome their fears and discover the true nature of the creatures, which might not be as menacing as they first seemed.
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.
First, choose the two universes you want to cross over. For example, if it's Amphibia and "Star Wars", know the key elements of both. Then, think of a reason for the crossover. Maybe a portal opens between the two worlds. Next, decide which characters from each will be the main focus. Start with an interesting hook, like a character from Amphibia suddenly finding themselves in the "Star Wars" galaxy.
One idea could be a Zyuohger crossover with the Power Rangers. The Zyuohgers could visit the Power Rangers' world and team up to fight a common enemy. They could learn from each other's fighting styles and share their technology.
One idea could be a Barbie crossover with Disney princesses. Imagine Barbie in the world of Cinderella, helping her get ready for the ball. Another could be a crossover with superheroes. Barbie could team up with Wonder Woman to fight some common villains. And a third idea might be a crossover with the Wizarding World. Barbie as a student at Hogwarts, learning magic and making new friends there.
Well, a fun dinosaur crossover fanfiction could involve dinosaurs and aliens. Maybe an alien race discovers Earth during the time of the dinosaurs and tries to either study or conquer them. This could lead to an epic battle between the two very different species. Or perhaps the aliens genetically modify the dinosaurs to create super - dinosaurs to do their bidding.
One idea could be a Shino crossover with Naruto in a modern-day setting. They could be students in a high - tech ninja academy where they have to use their skills in a more urban environment. For example, Shino's bug techniques could be used to track down digital threats or solve mysteries in the city.
A Kirby and Sonic the Hedgehog crossover fanfiction would also be cool. Imagine Kirby in the fast - paced world of Sonic. Kirby could learn to run super fast by swallowing a power - up in Sonic's world. They would have to race against time to stop Dr. Eggman from using Kirby's power - stealing abilities to take over both their worlds.
A crossover with Harry Potter would also be cool. Ichigo could attend Hogwarts as a transfer student. He'd probably be sorted into Gryffindor due to his brave nature. And he could use his Zanpakuto to fight off dark wizards.
Another great crossover could be Gowther in the 'One Piece' universe. Gowther could join the Straw Hat crew. His unique abilities would be quite useful during their adventures. He could use his memory - manipulation powers to deceive their enemies, like when they are facing the Marines or other pirates. And his rather naive nature about emotions could also lead to some comical and heartwarming moments within the crew.