Uub. He has so much potential as a character. He's the reincarnation of Majin Buu, but in a fanfic, we could explore his growth into a powerful fighter without the shadow of Goku always over him. He could form his own team and face new threats.
Launch. She has this really interesting dual - personality thing going on. In a fanfic, she could be developed more, perhaps having her own unique fighting style related to her two personalities.
Yamcha. He's often overlooked but has a lot of potential. In a fanfiction, he could go on a special training journey to a far - off planet and come back with new and powerful abilities. He could be given a more in - depth backstory about his time as a desert bandit and how that influenced his fighting style.
The Kimono Girls are often overlooked. They have a connection to the Legendary Beasts in Pokemon Gold and Crystal. A fanfic could focus on their daily lives, how they came to possess their special powers related to the Legendary Beasts, and their role in protecting the balance in the Johto region. Also, the Pokedex holders in these games, like Elm's assistants, could be given more spotlight. They might have their own dreams and goals aside from just helping the professor, and a fanfic could tell their stories.
Rock Lee could be an interesting character in this kind of fanfiction. He could use the Ninja Wire in his taijutsu - based combat, adding an extra element of surprise. Gaara might also be a good choice. He could use the wire in combination with his sand, perhaps using it to control the movement of his sand in more precise ways. Hinata could use the wire to enhance her gentle fist style, allowing her to strike from a greater distance while still maintaining the chakra - flow - based attacks.
Goku is often a main character in 'dragon ball futa fanfic'. His super - Saiyan forms and his never - ending quest for stronger opponents make him a popular choice. Vegeta is also commonly featured. His pride and his own journey to become stronger are great elements to build stories around.
The Prowler is a really underrated character. He has a cool look and an interesting backstory. In a fanfic, he could be a sort of anti - hero, someone who has his own code but doesn't always see eye - to - eye with Spiderman. Maybe he starts out as a foe but then they have to work together against a bigger bad.
Agent Madani is also somewhat underrated. Fanfiction could show more of her backstory and how she really feels about working in a world full of crime and violence. She could be given more complex relationships with other characters, not just Frank. For example, her interactions with other law enforcement agents or even some of the criminals she has to deal with.
Quicksilver could be one. In the movies, he didn't get as much screen time as he could have. In a multiverse fanfiction, he could be from a universe where his powers are even more enhanced and he plays a crucial role in a team - up. Another is Mockingbird. She has great combat skills and intelligence but isn't as well - known in the Avengers context. In a multiverse story, she could be a key figure in a different reality's Avengers.
Android 16. In the context of Dragon Ball Heroes, his peaceful nature and hidden power could be further developed. He could be a moral compass in a chaotic fanfiction story, and his relationship with the other characters, especially Gohan, could be deepened. Maybe he could be given new upgrades or abilities that make him more relevant in the battles against the villains.
Obviously, Percy himself would be a great character to feature. His charm and heroic nature would add a lot to the story. Annabeth is also a key character, especially if there are relationship - based spins in the bottle. Grover could be there too, providing some comical relief during the game. Another character could be Nico di Angelo. His mysterious nature would make for some interesting interactions during the spin the bottle scenarios.
One idea could be exploring an alternate timeline where Goku never hit his head as a child. He might grow up as a ruthless Saiyan warrior, changing the entire dynamic of the Dragon Ball universe.