Perhaps there is a situation where they have to team up to protect the Earth from a new threat. In the process, they discover feelings for each other that they hadn't expected. Their relationship then develops against the backdrop of this high - stakes adventure.
One idea could be Goten traveling back to the Saiyan - Saiyan war era. He could end up changing some small events that have big impacts on the future, like uniting some Saiyan clans earlier. This would create a whole new timeline where relationships between characters are different.
One idea could be that Goten and Trunks accidentally travel to an alternate dimension where their roles are reversed. Goten could be the more studious and reserved one while Trunks is the carefree fighter. They have to figure out how to get back while also dealing with the differences in this new world.
One idea could be that Gohan is teaching a self - defense class and Goten pretends to be a beginner to surprise everyone. Another is that Gohan's class is a seminar on Saiyan history and Goten adds some new perspectives from his own experiences.
One interesting plot idea could be that Goten and Trunks travel back in time to the Saiyan - Vegeta and Goku's father Bardock's era. They could end up changing some events that lead to a different future for the Saiyans. Maybe they prevent Frieza from destroying Planet Vegeta in a more creative way than expected, like by using some future technology to make the Saiyans seem more powerful than they actually are at that time.
One idea could be a story where Chichi and Goten go on a training adventure together. They face various challenges and Goten learns important life lessons from his mother.
A Goten and Harry Potter crossover could also be cool. Goten could be sent to Hogwarts by some magical accident. He would be the odd one out, not understanding the wizarding world at first. But his Saiyan strength could come in handy during the Triwizard Tournament, for example, when facing the dangerous tasks. Maybe he'd have to use his ki blasts instead of magic spells to get through certain challenges.
Perhaps a plot where they decide to take a honeymoon in an uncharted part of the universe. On their journey, they discover new planets, new species, and new powers. But they also run into some dangerous situations. This could test their relationship as a newly married couple and show how they support and rely on each other. It could also introduce some new characters that they befriend or have to fight against during their adventure.
Another idea is Goten traveling to the time when Goku first arrived on Earth. He could interact with a younger Goku, Piccolo, and the others. He might accidentally change the way Goku grows up, for example, by introducing some new training methods he learned in his own time. This could lead to Goku becoming even stronger much earlier and changing the battles against the Red Ribbon Army and later villains.
One interesting aspect could be their unique friendship. Goten is a Saiyan with a carefree nature, and Bra is a strong - willed character. Fanfictions can explore how they interact and support each other in different situations, like during a new threat in the Dragon Ball world.
Perhaps in the fanfiction, Superboy visits a parallel universe where everything is lemon - scented and lemon - colored. There, he meets an alternate version of himself who has a special connection to lemons, like being able to draw power from them. They team up to fight a common threat that is trying to destroy both universes.