A third idea could be a crossover adventure where Boruto and Naruto are transported to a different dimension. In this new world, they have to learn new ninjutsu and fight alongside new allies to find their way back home. It could also introduce some unique villains from this other dimension that challenge them in ways they've never been challenged before.
Another idea is a 'what - if' scenario. For example, what if Boruto was raised in a world where Naruto had failed to become Hokage? This could lead to a very different Boruto, perhaps more cynical or desperate to change the world on his own. The fanfic could explore how he would grow up and try to fix the situation his father couldn't.
Another interesting plot could be about a new villain that is a combination of the powers of all the previous villains in Naruto and Boruto. The characters would have to team up in new and unexpected ways to defeat this powerful foe. For example, Naruto and Boruto might have to combine their Rasengan and Vanishing Rasengan in a completely new way.
One idea could be a time - travel plot where Sarada goes back in time and meets a young Naruto. She could learn from his experiences and determination, and in turn, she might influence some of his decisions. This would create an interesting dynamic as they come from different generations but share common goals of protecting the village.
Maybe a fanfic where Naruto and Boruto are pitted against each other in a virtual reality battle. It could be part of a training exercise that gets out of control, and they start using their real skills and emotions, leading to a intense and revealing fight.
A plot where Naruto and Boruto have to team up to fight a new, powerful enemy that neither could defeat alone. This would allow for some great father - son bonding moments and also show how their skills complement each other. For example, Naruto's brute strength combined with Boruto's unique ninja techniques. It could also explore how Naruto imparts his wisdom about the ninja way to Boruto during the battle.
One idea could be exploring a different path for Boruto where he doesn't inherit the power of the Jougan. Maybe he focuses more on his own unique ninja skills that he develops through intense training with his friends. For example, he could create a new type of jutsu by combining the elements in an unexpected way.
One plot idea could be Boruto getting lost in a mysterious forest during a training exercise. Naruto and Hinata then team up to find him. Along the way, they face some old enemies or new threats that test their skills and their relationship as a couple. Another idea is that Boruto discovers a hidden power within himself that Naruto doesn't understand, and Hinata has to be the one to bridge the gap between father and son by helping Naruto understand Boruto's new ability.
A cool Naruto and Boruto fanfiction concept could be exploring the relationship between Sasuke and Boruto in more depth. Maybe Sasuke takes Boruto on a special training mission, similar to how he trained with Naruto in the past. This would allow Boruto to understand Sasuke's way of thinking and his past better. Also, a story where all the Konoha 11 have kids and they all train together could be interesting.
Another interesting OC could be a descendant of a minor clan that has long been forgotten. This OC could discover ancient scrolls or techniques that were lost over time and strive to bring their clan back to its former glory within the Boruto universe. They might face challenges from the established clans who see them as a threat.
One idea could be a time - travel fanfiction where Boruto goes back in time and meets a young Naruto. He could help Naruto avoid some of the hardships he faced. Another could be a story where Sarada has to team up with Naruto to save Boruto from a new and powerful enemy. It would be interesting to see their different fighting styles and how they interact.
In a Boruto Yaoi Harem Fanfic, you could play with the concept of power dynamics. Some characters in the harem might be more powerful than Boruto in certain ways, and this could create interesting scenarios. For instance, a powerful ninja in the harem could use his strength to protect Boruto, but at the same time, Boruto's own charm and potential could be what attracts the others. You could also include some cultural elements from the Naruto universe, like different clans' traditions, and see how they affect the relationships in the harem.