Obviously, Gohan would be the main character. Videl could also be in it as a classmate or a potential love interest. Piccolo might keep an eye on Gohan from afar to make sure he doesn't get into too much trouble. And of course, Gohan's friends from previous adventures could make cameo appearances, like Krillin dropping by the school sometimes.
In this fanfiction, Gohan might face the challenge of hiding his Saiyan powers from his classmates. He could also make new friends who are interested in different things like academics or sports, and he has to balance his high school life with his training as a Saiyan warrior.
Well, he might use his powers secretly. Like, he could use his super speed to be on time for every class without even breaking a sweat. And when there's a bully in school, he could give them a little scare with his strength, but not too much to expose his true identity.
Often, his friends at high school can be important characters too. They might be normal humans who are curious about Gohan's sometimes strange behavior. And of course, his family members like Chi - Chi could make appearances, maybe giving Gohan advice on how to balance school and home life.
One interesting plot could be Gohan trying to balance his Saiyan powers with high school life. For example, he might accidentally use his super strength during gym class and have to cover it up.
One great fanfiction could be about Gohan and Piccolo's training sessions. Gohan, with his Saiyan - human hybrid power, and Piccolo, the Namekian, could be exploring new ways to increase Gohan's power. Maybe they discover a new technique while sparring in the wilderness. This would not only strengthen their bond as mentor - student but also as friends who rely on each other in battles against stronger foes.
One possible fanfiction could be about Bulma helping Gohan with his studies. Since Bulma is super smart, she could tutor Gohan in advanced science and technology. This would not only strengthen their friendship but also give Gohan new knowledge that might come in handy during his battles. For example, understanding the principles of energy and mechanics could help him better strategize against his enemies.
He could simply avoid using his powers in front of others as much as possible. For instance, if there's a fight, he'd try to resolve it verbally instead of using his fists.
One great fanfiction could be 'Gohan and Goten's Training Adventure'. It shows them training together in a unique way, exploring new techniques and facing challenges that the original series didn't cover. It really captures the essence of their relationship as brothers and their growth as Saiyans.
One idea could be Gohan in his Super Saiyan 4 form facing a new, powerful enemy from another dimension. He could struggle at first to control the raw power of this form while also trying to protect his friends and family. Maybe this new enemy has the ability to nullify the Saiyan's energy attacks, forcing Gohan to rely more on his martial arts skills that he learned from Piccolo.