A great idea for Raditz crossover fanfiction is a crossover with the Star Wars universe. Raditz could be mistaken for a strange alien species in the Star Wars galaxy. He might get involved in the conflict between the Jedi and the Sith. His Saiyan abilities would be a huge advantage in lightsaber battles. He could also form an alliance with the Rebels or be lured to the dark side by the Sith, depending on how the story unfolds.
One idea could be a crossover with the Dragon Ball Z and the Naruto universe. Raditz could land in the Hidden Leaf Village and cause chaos, leading to battles with powerful ninjas like Naruto and Sasuke. Another idea is a crossover with the One Piece world. He might end up on the Grand Line and get involved in the Straw Hat Pirates' adventures. Maybe he would try to steal their Devil Fruits or be forced to team up with them against a common enemy.
Maybe Raditz gets sent to an alternate universe in Dragon Ball Super. There, he meets different versions of the Z - fighters. He has to team up with them to fight a common enemy that is threatening both universes. This would allow for some cool battles and character development for Raditz as he learns from these new allies.
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.
One plot idea could be that Gohan's friends, like Krillin and Bulma, team up to rescue him. They might use some of Bulma's inventions to track Raditz. Another idea is that Gohan manages to outwit Raditz during the kidnapping. Maybe he uses his hidden power to escape Raditz's clutches briefly and leaves a trail for his father Goku to follow.
There might be a fanfiction where Raditz survives and teams up with Goku against a new, more powerful enemy. They have to put aside their differences and learn to work together. Raditz could start to respect Goku's strength and his way of life.
A Rambo crossover fanfiction could involve him crossing over into the Star Wars universe. Rambo's guerilla warfare tactics could be interesting in a galaxy far, far away. Maybe he helps the Rebel Alliance in a ground - based battle against the Empire. Or a crossover with the Predator series. Rambo would be a worthy opponent for the Predator, and the fight between them in the jungle could be epic. Also, a Rambo and John Wick crossover would be intense, two highly skilled fighters on the same side or perhaps initially at odds.
One idea could be a crossover with a modern military setting. The Decepticons could be trying to steal advanced military technology. Another is a crossover with a post - apocalyptic world where they are competing with other factions for resources. A third could be a crossover with a magical realm, with the Decepticons trying to harness the magic for their own evil purposes.
One idea could be a crossover with Naruto. Kakuzu could be sent to the Naruto universe and form an unlikely alliance with a shinobi village to fight a common enemy, like the Akatsuki from his own world turned rogue in the new universe. This would create a lot of interesting character dynamics and battles.
Another option is a crossover with 'The Little Mermaid'. The characters from the descendants could meet Ariel and her friends underwater. Evie might be interested in the mermaid fashion and could design new outfits inspired by the underwater world.
Another possibility is a crossover with the world of Naruto. The characters from MHA could participate in the Chunin Exams. Bakugo might be really into showing off his skills in this new and different kind of competition.
One idea could be a Venom crossover with Spider - Man in an alternate universe where they have to team up against a common enemy like Carnage. Another could be a Venom and Deadpool crossover, with their crazy personalities clashing and then somehow working together. Maybe a Venom crossover with the X - Men, where Venom's alien nature causes some interesting reactions among the mutants.