One idea could be a crossover where the characters from RWBY and Dragon Ball Z have to team up to fight a common enemy. For example, the Grimm from RWBY could be combined with some of the villains from Dragon Ball Z, like Frieza. The RWBY characters could learn some of the ki techniques from Dragon Ball Z, and in return, the Dragon Ball Z characters could learn about the unique Dust powers in RWBY.
An interesting concept could be a fanfic set in a world that combines the settings of RWBY and Dragon Ball Z. The academies in RWBY could exist alongside the martial arts dojos in Dragon Ball Z. Characters like Weiss could interact with Vegeta, and there could be a power struggle between the different factions. Weiss might try to prove that her Dust - based magic is as powerful as Vegeta's ki blasts.
Maybe a fanfic where Ruby Rose meets Goku. Ruby could be amazed by Goku's super strength and his ability to transform. Goku, on the other hand, might be interested in Ruby's scythe and her speed. They could have a friendly sparring match where they both learn from each other's fighting styles.
One idea could be to have Goku and his friends end up in the RWBY world. They could team up with Team RWBY to fight a common enemy. For example, the Saiyans' power levels would be a huge asset against the Grimm. Another idea is to have Ruby Rose gain the ability to use Ki like in Dragon Ball Z. This would change the way she fights and add a new dimension to her character.
One idea could be a crossover where Ruby and her team encounter the Saiyans. Maybe they team up to fight a common enemy that threatens both Remnant and the Dragon Ball universe. For example, a powerful demon or an ancient evil that has the power to destroy multiple dimensions.
One idea could be Shaggy getting transported to the Dragon Ball Z universe and accidentally eating a Senzu bean, which gives him superhuman strength and he has to figure out how to control it. Another could be Shaggy befriending Goku and teaching him some of his laid - back ways while Goku teaches Shaggy how to fight.
One idea could be a new villain from an unknown dimension arriving in the Dragon Ball universe. This villain has a unique power that nullifies ki attacks, forcing the Z fighters to rely on their martial arts skills alone.
One idea could be exploring a dimension where the Saiyans never lost their planet and became a peaceful, advanced civilization. Another could be a dimension where the Z - fighters have to face off against versions of themselves that are corrupted by dark magic. Or perhaps a dimension where the Dragon Balls have different wishes and limitations.
One idea could be a gamer getting transported into the Dragon Ball Z universe and having to learn the ki techniques like a newbie Saiyan. They could start from the very bottom, training with Goku or Vegeta, and slowly rise in power. Another could be a gamer who has the ability to hack the Dragon Ball Z game world in a way that changes the rules, like making the Dragon Balls more accessible but with a new set of challenges to face when using them.
One interesting crossover could be a battle between Hulk's brute strength and Goku's Super Saiyan power. Maybe in the fanfic, they start off as rivals, with Hulk misunderstanding Goku as a threat to Earth. Their fight would be epic, with Hulk's limitless rage against Goku's increasing power levels. It could also explore how their different universes' power systems interact.
One idea could be a crossover where Naruto characters gain the ability to use Dragon Ball Z techniques. For example, Naruto using the Kamehameha wave. It would be a cool blend of the two universes.
Well, for 'Ben 10 Dragon Ball Z fanfiction', a cool concept could be that Ben gets caught in a time - space rift that sends him to the Dragon Ball Z universe right when a new and powerful enemy is emerging. Ben has to quickly figure out how to use his Omnitrix in this new world while also trying to get back home. And perhaps some of the Dragon Ball characters are intrigued by the Omnitrix and want to study it, leading to some funny and interesting interactions.
Another interesting concept would be Shallot getting lost in a different dimension within the Dragon Ball Z universe. He would have to find his way back while encountering strange new races and powers, and along the way, he might learn some valuable lessons about himself and his abilities. This could lead to him coming back to his own world as a much stronger and wiser fighter.