Perhaps the characters from the Future Diary world end up in the Naruto universe. Yuno could form an interesting relationship with Naruto. She might see his strong will and be both intrigued and challenged by it. They could team up to fight common enemies, with Yuno's unpredictable and often violent nature contrasting with Naruto's more positive and forgiving attitude.
One idea could be to explore what would happen if Yuno was a pacifist from the start. Instead of her violent ways, she tries to win the survival game through cooperation and strategy. Another could be a story where the rules of the Future Diaries are changed slightly, like the diaries predicting different time frames or having limited visibility. Also, a fanfiction where the characters are transported to a different world while still having their diaries could be really cool.
One idea could be exploring an alternate universe where the rules of the Future Diaries are different. For example, instead of 12 diaries, there are only 6, but with more powerful abilities. Another idea is to focus on the backstories of the minor characters in the original series. Maybe give them their own diaries and show how they would compete in the survival game.
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.
In 'Naruto Future Memories Fanfiction', there could be a plot where Naruto's future memories show a world where the ninja villages have all been destroyed. He then has to find a way to change the course of history. He may start by looking into the root causes of the destruction in his memories, like a powerful and evil enemy that no one was prepared for. He might then gather all the ninja villages together to form a united front against this potential threat, using his knowledge from the future memories.
One idea could be an OC who is a time - traveler from the future. They come back to the Naruto world to prevent a great disaster that they know will occur in the future. This OC could have unique powers related to time manipulation or future - sight.
One interesting plot idea could be Naruto's son, Boruto, facing a new and powerful enemy that has ties to an ancient evil from the past that was thought to be sealed away long ago. This enemy could be manipulating the new generation of shinobi in the Hidden Leaf Village, causing chaos and mistrust among them.
One idea could be that Future Rogue travels back in time and meets Lucy before the events of the main story. He initially hides his true identity but gradually forms a bond with her as they go on adventures together. They might face a common enemy that only their combined powers can defeat.
A possible plot could be that in the future, both Tom and Tord are leaders of their own factions. They start off as rivals but gradually realize that they can achieve more by joining forces, and in the process, a romantic relationship begins to develop between them as they understand each other better.
One idea could be that in a post - apocalyptic future where Trunks is the last hope, Broly somehow appears. Maybe Broly has lost his memory and Trunks tries to train him to use his power for good. Another plot could be a time - travel accident that brings Broly to Trunks' time. They initially fight but then realize they need to team up against a common enemy like a new form of the Androids.
One idea could be exploring how Naruto's children deal with new threats to the Hidden Leaf Village. Maybe they face a villain who has found a way to use ancient, forbidden jutsu that Naruto and his friends had long forgotten about.