A crossover with One Piece might also be cool. Imagine Luffy and Goku teaming up. Luffy's rubber abilities combined with Goku's super strength could make for some really fun and unique battle scenes. They could be on a quest to find a powerful treasure that has both the power of the One Piece world and the Dragon Balls.
First, decide which universe you want to crossover with. For example, if it's with the DC Comics universe, think about which characters would interact well with Dragon Ball characters. Then, come up with a basic plot. Maybe the Dragon Balls are a threat to the DC world and Superman has to work with Goku to stop them from being misused.
Vegeta could be paired with Ike. Both are strong - willed and prideful characters. They would initially clash due to their similar personalities, but as they face a powerful enemy together, they would come to respect each other. Vegeta's Saiyan power and Ike's swordsmanship would make for an interesting combination in battles. They could also have some great banter as they compare their respective power levels and combat philosophies.
One idea could be to combine the power - up mechanics of Dragon Ball Z with the strategic battles of Fire Emblem. For example, characters in the fanfic could gain new abilities similar to Super Saiyan transformations during intense battles in the Fire Emblem - like battlefields. They could use these new powers to turn the tide of the fight against the enemy forces, which could be a mix of both Dragon Ball Z villains and Fire Emblem antagonists.
The plot might involve a villain who has the ability to steal both ki and chakra. This forces Goku and Naruto to team up. Goku, with his Super Saiyan forms, provides brute strength, while Naruto, with his various jutsu like Rasengan and his Sage Mode, offers strategic combat skills. They would have to combine their powers in unique ways to defeat this new threat.
One possible plot could be that the villains from GT, like Baby, somehow find a way to cross over into the Super universe. Goku and Vegeta from Super would then have to team up with their GT counterparts to stop Baby from taking over the entire multiverse. They would need to combine their powers, like Super Saiyan Blue and Super Saiyan 4, to stand a chance against this powerful foe.
One idea could be a crossover with other popular anime like Naruto. Picture Goku meeting Naruto and having a friendly sparring match. Another could be a crossover with the DC Universe, where Vegeta and Superman have a showdown to see who's stronger. Or perhaps a crossover with the Final Fantasy series, with the Dragon Ball characters in a world filled with magic and summons.
One idea could be that Goku and Naruto meet during a universal tournament. Goku, being his usual self, is excited to fight strong opponents. Naruto, on the other hand, is intrigued by Goku's pure love for combat. They could team up against a powerful enemy from another dimension who threatens both their worlds.
It's hard to say for sure. Goku has the ability to reach extremely high power levels and transform into powerful forms like Super Saiyan God. However, Naruto also has the power of the Nine - Tails and his own Sage Mode, which makes him incredibly strong. If they were to fight, it would depend on the circumstances, like the location and if Naruto could use his ninja tricks to his advantage.
Another theme is friendship. Since both Naruto and Dragon Ball Z have strong themes of friendship, when they cross over, the fanfics often explore how Naruto and Bulma can become friends. They come from different worlds but end up having to rely on each other, which is a great way to show the power of friendship across universes. In some fanfics, they also make new friends together from both universes.