Maybe in the fanfiction, Goten and Future Trunks meet when Future Trunks comes to the present for some reason. Goten is really excited to meet him as he has heard so many stories. They start comparing their Saiyan powers. Goten shows off his new techniques while Future Trunks shares his knowledge of the future threats. Eventually, they find themselves in a race against time to stop an approaching danger that Future Trunks foresaw.
One possible plot could be that Goten and Future Trunks meet during a time - traveling accident. They initially have some misunderstandings due to their different upbringings and experiences. But as they start to train together, they learn from each other's fighting styles and develop a deep friendship. They then team up to face a new, powerful enemy that threatens both their timelines.
The plot could also focus on their relationship. Since they are brothers but from different timelines in a way. They could bond over family stories that Goten has heard but Gohan can now give a different perspective on, like stories about their father. And they might train together to become even stronger for the future battles that Gohan foresees.
It could be a rogue Saiyan from an alternate timeline who has come to their universe to prove his supremacy. He is jealous of the power that Goten and Future Trunks possess and wants to take it for himself.
One possible plot could be that in a post - apocalyptic future, Gohan and Trunks team up to fight against a new and powerful enemy that has emerged. They train together, with Gohan sharing his knowledge of the old martial arts techniques and Trunks bringing in his own combat skills developed from years of fighting alone. Their bond grows stronger as they face challenges, and eventually they manage to defeat the enemy, saving what's left of the world.
In a 'Vegeta meets Trunks' fanfiction, a great plot could be centered around Vegeta finally opening up to Trunks about his own insecurities. Vegeta has always been this tough exterior, but he might share with Trunks his fears about not being able to protect their family or the Saiyan race. This would be a very emotional moment for both of them. Trunks would see a different side of his father, and Vegeta would be taking a big step in their relationship.
In this fanfiction, it could be that King Vegeta mistakes Trunks for a threat at first. But Trunks explains his purpose, which is to protect the Saiyan race. King Vegeta then decides to train Trunks in the traditional Saiyan ways. This training helps Trunks become even stronger and also bridges the gap between their two different generations of Saiyans.
Well, in the world of fanfiction, the possibilities are endless. Goten and Trunks are popular characters, and while not all fanfictions will feature them kissing, there are likely some that do. It really depends on the creativity and interests of the fanfiction authors. Some might write it in a more innocent, platonic way, while others could be more romantic. You have to dig through the vast collection of fanfictions to find the ones that match what you're looking for.
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.
Well, they might change some major events. For example, they could prevent a big battle that had a lot of casualties in the original timeline. Maybe they'd help their parents at a younger age, giving them an edge in fights. They could also introduce new techniques to the past, which would change the power balance among the Z - fighters.
It could involve time travel. Maybe a character from 'the order' travels to the future and has to adapt to new magical or technological advancements there. They might encounter new forms of magic or face challenges that the future presents.
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.