Perhaps a story about a human martial artist who trains under the Z - fighters. This human could bring a unique perspective to the group and face challenges that are different from the Saiyans or other aliens in the DBZ universe. They might struggle with feelings of inferiority compared to their super - powered comrades but find their own strength in the end.
One idea could be exploring the life of a human who gains Saiyan-like powers through some scientific experiment gone wrong. They then have to learn to control these new powers while hiding their secret from the world.
Perhaps a fanfiction about a human who has a special bond with the dragon balls. This human is strong not just physically but also in terms of their spiritual connection to the dragon balls, which gives them unique powers and the ability to influence the wishes made on the balls.
One interesting idea in dbz fanfiction is the exploration of alternate universes. For example, what if Goku had been raised on a different planet? Another is the development of relationships between characters that weren't fully explored in the original series, like a deeper friendship between Vegeta and Piccolo. Also, some fanfictions focus on power - ups for minor characters, giving them a chance to shine in battles.
One interesting concept could be new power - up forms for the characters. For example, imagining Goku or Vegeta achieving a form that combines the super human strength with a new type of ki control. Another concept might be alternate universes where the rules of the DBZ world are slightly different, like in one universe Saiyans have a different weakness or strength.
One idea could be a crossover where Goku from DBZ ends up in the Supernatural universe and has to team up with the Winchester brothers to fight demons. He could use his ki blasts against the hordes of hell.
One idea could be to explore what if Gohan had a different training partner before the Cell Games. For example, if Piccolo had trained with him more intensively, it might have changed his power level and fighting style during the games.
One idea could be a battle between Goku and Superman to determine who is the strongest in the universe. They might start off as rivals but then realize they have more in common than they thought and team up against a greater threat like Darkseid and Frieza combined.
Well, in a dbz justice league fanfiction, there could be a plot where the power levels of the Justice League members are measured using the scouters from DBZ. This could lead to some interesting reactions. Superman might have an off - the - charts power level that astonishes the Z - fighters. At the same time, the Justice League could learn some ki - based techniques from the DBZ characters. For instance, Aquaman could learn how to fly using ki, which would be a huge advantage for him in underwater and above - water battles.
One idea could be that Goku ends up in the world of Aladdin. He might mistake the flying carpet for a new kind of Ki - powered vehicle. And he could use his martial arts skills to help Aladdin fight off Jafar's minions in a really action - packed way.
Another interesting concept is to cross them over with a fantasy world. Saiyans could be in a world full of magic and mythical creatures. Picture Vegeta having to deal with dragons that can talk and cast spells. Their Saiyan pride might get in the way at first when they realize that their brute strength isn't always enough in this new world.
A cool concept could be that Vegeta gets transported to Gotham City. He initially clashes with Batman due to their different methods, but they eventually work together to take down a powerful new enemy that is a threat to both their worlds.