In a Gohan x Goku fanfic, their relationship can be delved into by creating scenarios where they have to rely on each other completely. For example, if they are in a situation where Goku's strength and Gohan's intelligence are both required to escape. Their different personalities can also be highlighted. Goku's carefree nature contrasted with Gohan's more studious and responsible side. And of course, flashbacks to Gohan's childhood and how Goku's presence or absence affected him can add depth to their relationship.
For Naruto, it could accelerate his growth not just in terms of power but also in maturity. Spending a long time alone in the chamber, he might have deep self - reflections and come out with a better understanding of his purpose and responsibilities.
One idea could be Naruto using the hyperbolic time chamber to train intensively for a new and extremely powerful jutsu. He could emerge with a whole new set of skills that surprise his friends and foes alike.
In the manga, Gohan never managed to defeat Goku. Their battles often ended with Goku coming out on top or the fight being interrupted for some reason.
In a fanfiction where Future Gohan meets Goku, it could be an emotional reunion. Gohan might be filled with a sense of relief and joy, seeing his father again. He could show Goku all the things he's been through in the future, and Goku would be both proud and sad about what his son has endured.
In the 'goku and gohan betrayed fanfiction', perhaps they are betrayed due to a misunderstanding. Say, Goku makes a deal with an unknown force to save the universe, but it's misconstrued as him allying with the enemy. Gohan, being associated with Goku, is also seen as a traitor. And this misunderstanding could be spread by a character with their own motives, like a power - hungry individual who wants to take over the Z - fighters' leadership.
It could be Vegeta. Maybe in this fanfiction, his pride gets the better of him and he feels overshadowed by Goku and Gohan's power. So he fabricates some lies to make them look like traitors to the rest of the group.
Common themes include the father - son relationship. This is explored in different ways like Goku's absence at times and how it affects Gohan and then how they reconnect. Another is the exploration of Gohan's potential. Goku is usually there to unlock that potential. There are also themes related to the Saiyan culture. How Goku passes on knowledge about their race to Gohan and how Gohan uses that knowledge in battles and in life.
In the fanfiction, perhaps they team up to fight a common enemy. Goku's raw power combined with Gohan's strategic mind from the future battles could make them an unbeatable duo. They'd exchange blows and strategies, and their teamwork would be amazing to read about.
Well, a plot could involve Gohan and Goku getting trapped in a time - loop. They keep reliving the same day over and over, and each time they try different strategies to break free. This would give them a chance to have deep conversations about their lives, their hopes, and their fears. Or perhaps a story where Goku is injured and Gohan has to take on the role of protecting the Earth alone for a while, with Goku guiding him from the sidelines. Also, a fanfic where they both enter a tournament in an alternate universe where the rules are very different from what they're used to could be interesting.