One interesting aspect could be the unique character interactions. For example, seeing how Trunks from different universes or timelines interact with characters he might not have met in the original story. It can lead to fresh and unexpected story developments.
I'm not sure of specific titles off the top of my head, but you can try searching on fanfic platforms like Archive of Our Own. Look for ones with high ratings and a lot of reviews. Usually, those are the ones that are well - written and engaging.
The female characters in Fire Emblem might be intrigued by Trunks. His otherworldly appearance and his chivalrous nature could attract their attention. He could also be protective of them, especially in battles. And in return, they could introduce him to the local customs and traditions, which he would find quite different from his own world. For example, he might be invited to a local festival and be amazed by the music, dancing, and food.
In a fanfic like this, the cultural clash would be interesting. Future Trunks comes from a world of high - tech and space travel, while the Fire Emblem world has its own medieval - like setting with magic and knights. He could introduce new ways of fighting and thinking to the Fire Emblem characters. For example, his knowledge of energy blasts might inspire some mages to try and develop similar attacks using magic. And the Fire Emblem characters could teach him about the use of magic and the importance of strategy in battles, which is different from his more straightforward combat style in his own world.
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.
One popular Trunks Crossover Fanfiction is 'Trunks in the DC Universe'. It explores what would happen if Trunks landed in the DC world and interacted with heroes like Superman and Batman. It's really exciting to see how his Saiyan powers would be perceived in that different universe.
Time travel is a common theme. Since Mirai Trunks is from a future timeline, many fanfictions play around with his ability to travel through time and how it affects the crossovers. For example, he might accidentally end up in a different universe during a time - travel attempt.
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.
Well, there's a fanfic called 'Trunks' Time - Travel Tales' that's really good. It plays around with the concept of Trunks' time - traveling in a very creative way. Then there's 'Future Trunks' Love Story' which, as the name suggests, focuses on his romantic relationships. Also, 'The Legend of Future Trunks' is a must - read as it expands on his character and his place in the Dragon Ball universe.