In some fanfictions, the guild system from Fairy Tail could be introduced to the Dragon Ball Super universe. The Z - fighters might form a guild of their own. Vegeta, with his pride, could be a bit reluctant at first but then see the benefits of working together as a guild. They could take on missions similar to the ones in Fairy Tail, like protecting planets instead of villages.
One common plot idea is a crossover where characters from Fairy Tail and Dragon Ball Super meet. For example, Natsu from Fairy Tail could team up with Goku from Dragon Ball Super to fight a powerful villain that threatens both their universes.
One interesting crossover could be a battle between Naruto's Rasengan and Goku's Kamehameha. It would be epic to see the different energy forms collide. Maybe Naruto could learn some of Goku's training techniques and vice versa, like Naruto trying to achieve Super Saiyan levels of power or Goku learning about chakra control.
One interesting crossover could be Ben Tennyson using his Omnitrix to transform into an alien with powers similar to a Saiyan. For example, he could transform into an alien that can increase its power level like a Super Saiyan. Another could be the characters from Dragon Ball Super being intrigued by Ben's ability to change forms so quickly and effortlessly.
One interesting crossover could be the characters' power - ups. For example, Sora from Kingdom Hearts might learn some ki - based attacks from the Dragon Ball Super characters. This would be a cool blend of the two universes' fighting styles.
One interesting crossover could be the power - up systems. In Dragon Ball Super, characters achieve new forms like Ultra Instinct. In Highschool DxD, Issei has his Boosted Gear. A fanfiction could explore what would happen if Issei somehow got access to the Saiyan power - up system or if a Saiyan character got ahold of the Boosted Gear. Maybe the Saiyan's natural battle instincts combined with the Boosted Gear's power would create an incredibly powerful being.
There could be a fanfiction where the magic system of Fairy Tail is introduced to the Dragon Ball universe. Characters in Dragon Ball start to learn and use magic, which leads to all kinds of new adventures and power - ups. For example, Vegeta might struggle to master Fairy Tail's lightning - based magic while still maintaining his Saiyan pride.
A fanfiction could explore what would happen if Natsu from Fairy Tail learned the Kaioken technique from Goku in Dragon Ball Z. Maybe he uses it in a fight against a really strong opponent in the Fairy Tail world, but has trouble controlling the power at first, leading to some comical and intense situations.
A really cool concept could be the Warhammer magic items being introduced to the Fairy Tail world. Imagine if Gray got his hands on a Warhammer frost weapon. It could enhance his ice - make magic in ways he never thought possible. And the different magical lore from Warhammer could inspire new spells among the Fairy Tail mages.
One interesting crossover could be Goku meeting Elsa. Goku might be intrigued by Elsa's ice powers and try to spar with her. He could learn a lot about controlling power from Elsa as she has to constantly keep her emotions in check to avoid causing too much ice mayhem, much like how Goku has to control his Saiyan rage.
A really cool crossover concept could be the sharing of techniques. Spiderman could learn how to use Ki blasts from Goku or Vegeta. In return, he could teach them some of his acrobatic fighting moves. This exchange of skills would create some really unique and exciting battle scenes in the fanfiction, as they combine their different fighting styles to take on common enemies.