One idea could be that Broly is transported to an alternate universe where he teams up with Goku from a different timeline to fight a new, powerful enemy. They have to combine their unique fighting styles to stand a chance.
Well, a plot could be centered around Broly's origin. In this fanfiction crossover, it could be revealed that Broly has a connection to an ancient race in a different part of the Dragon Ball universe. Goku and Vegeta discover this and together with Broly, they embark on a journey to uncover the secrets of this race. Along the way, they face various challenges and battles, and Broly has to control his power better to help his new allies.
A Broly crossover with the Naruto universe could be really cool. Picture Broly in the Hidden Leaf Village, his incredible power causing quite a stir. Maybe he could get involved in the fight against the Akatsuki, using his brute strength in a world of ninjas. It would be interesting to see how he adapts to chakra and ninja techniques.
Trunks would also be a great choice. Trunks is from the future and has a different set of skills and experiences. He could introduce Broly to some new technology or fighting techniques from his own timeline. And together, they could face threats that neither could handle alone, like a time - traveling villain.
One idea could be a crossover with the Naruto universe. The Saiyans could learn about chakra and how to use it, while the ninjas are amazed by the power of ki. Another could be a time - traveling plot where the Dragon Ball Heroes characters end up in the past of their own world and have to prevent a major catastrophe that changes the course of their history. Maybe a crossover with One Piece where they search for the One Piece together and face off against the powerful pirates and the Marines.
One idea could be that Goku and Naruto meet in a strange dimension. They initially mistake each other for an enemy but then realize they have a common goal, like saving both their worlds from a new powerful villain. Goku could teach Naruto some of his ki control techniques, and Naruto could show Goku some of his more unique jutsu.
One idea could be a crossover with the Naruto universe. Goku and Naruto could team up to fight a common enemy. Maybe they face an evil villain who has the power - stealing abilities like Cell and the ability to use powerful ninja jutsus. Another plot could be a crossover with One Piece, where Luffy and Goku have a friendly competition about who can eat more food and then end up having to work together to defeat a new threat at sea that has the strength of Saiyans and the deviousness of pirates.
A possible plot for the crossover fanfiction could be that Ruby discovers a way to travel to the Dragon Ball universe. There, she meets Goku and the others and learns about ki and the different power - ups. She then brings this knowledge back to Remnant and tries to teach her friends. At the same time, some of the Dragon Ball characters could be curious about Remnant and follow Ruby back. This leads to a series of adventures where they have to deal with both the Grimm and the power struggles in Remnant, all while trying to understand each other's worlds better.
Well, a cool plot for Dragon Ball Xenoverse Crossover Fanfiction could be a time - traveling crossover. Imagine characters from different anime universes being brought to the Dragon Ball Xenoverse timeline. For example, characters from Fullmetal Alchemist arrive in the Xenoverse. Edward could use his alchemy skills against the Dragon Ball villains, and Alphonse could have some really interesting interactions with the Dragon Ball characters, like Bulma or Master Roshi.
One idea could be a crossover with the Naruto universe. Imagine Goku and Naruto teaming up to fight a common enemy like a powerful, evil entity that combines the worst aspects of the Akatsuki and the Red Ribbon Army. They could learn from each other's fighting styles, with Naruto teaching Goku about chakra and Goku showing Naruto the power of ki.
One idea could be a crossover with the Naruto universe. Goku and Naruto could have an epic battle or team up against a common enemy. Another idea is a crossover with One Piece, where the Z - fighters join Luffy's crew for a while. Or perhaps a crossover with Harry Potter, where the Dragon Ball characters have to deal with magic in the wizarding world.