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.
Future Trunks could tell a story about how he traveled through time to seek help from Goku and the others. It was a desperate move to save his own timeline which was being decimated by the Androids. He had to leave his mother and friends behind in a world full of danger, and his journey through time was filled with uncertainty and hope at the same time.
One great 'Best Future Trunks Crossover Fanfiction' is 'Trunks and the Multiverse Adventure'. In this fic, Trunks travels across different universes and teams up with various versions of the Z - fighters. It has an exciting plot with lots of action and character development.
One common theme is time - travel adventures. Since Future Trunks is known for his time - traveling, fanfictions often explore different time - travel scenarios involving his female counterpart. For example, she might go back in time to change certain events in the Dragon Ball timeline.
Perhaps a plot where Future Gohan and Future Trunks accidentally travel to an alternate timeline. There, they have to team up with different versions of themselves to defeat a common enemy. This would involve exploring how they interact with these alternate selves and how they adapt to the new environment and challenges.
A good 'Best Future Trunks Crossover Fanfiction' should first and foremost stay true to Trunks' character. His determination, his sense of justice, and his complex relationship with his timeline are all important aspects to maintain. For example, if he's crossed over into a different universe, his reactions to the new environment should be in line with what we know of his personality.
Gohan would be a great character to pair with Future Trunks in a crossover fanfic. Their friendship and combined power could make for an interesting dynamic. In a crossover, they could support each other in a new and unfamiliar world. Another good option is Vegeta. Since Future Trunks is his son, their relationship could be explored further in a different setting. They could also team up to fight stronger enemies. Also, Bulma could be paired with Future Trunks. She could use her scientific knowledge to help them in a crossover situation, like building new gadgets or finding a way home.
One idea could be a crossover with the Dragon Ball Super universe where Future Trunks teams up with Goku Black from an alternate timeline. They could be forced to work together against a new, powerful enemy that threatens both their timelines. Another plot could involve a crossover with the Naruto universe. Future Trunks could end up in the Hidden Leaf Village and learn about chakra. He might then combine his ki powers with some ninja techniques to fight a common foe. A third idea is a crossover with the One Piece world. Future Trunks could land on the Grand Line and join forces with the Straw Hat Pirates. They would have to face off against the Marines and other pirates while also trying to find a way for Trunks to get back to his own world.