One interesting fanfiction could be about Future Trunks exploring new time - traveling adventures. Maybe he discovers a parallel universe where the Z - fighters have different powers and he has to adapt quickly to survive.
Future Gohan's character development would likely involve him becoming more resolute and determined. After all the hardships he's faced, he would grow stronger both physically and mentally. He might start as a somewhat broken hero, but as the story progresses, he'd regain his confidence and find new purpose in protecting what's left of his world.
One interesting fanfiction could be about Future Trunks training in a new dimension. Maybe he discovers a unique form of energy there and has to master it to save his timeline again.
Another good pairing could be with Bulma. Since she is his mother in his own timeline, but in fanfiction, they could have a different kind of relationship. Maybe she helps him with some advanced technology to enhance his fighting abilities.
Gohan would be a great character to pair with Future Trunks. They are both strong and have a deep connection to protecting the future. Their combined power and intelligence could make for some really exciting storylines.
Another possible ending is that Gohan sacrifices himself to defeat Cell. He could use a self - destructive move that not only takes out Cell but also costs Gohan his life. This would be a very dramatic and tragic ending, but it would also show Gohan's selfless heroism.
In this fanfic, Gohan might encounter different versions of his friends and enemies. He could see how the future has been shaped by past events. Maybe he meets a future version of himself who has become much stronger or has different values.
Definitely their strong bond. They have been through so much together, so highlighting their loyalty and trust for each other is great. Also, their different fighting styles can add action - packed scenes. For example, Gohan's more methodical and strategic approach against Trunks' more impulsive and aggressive style.
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.