One possible storyline could be Naruto using his ninja skills in a medical way. For example, he might use his speed to quickly respond to emergency cases in the hospital. He could also use his chakra control to perform precise surgeries that normal doctors couldn't. Maybe he'd develop a new medical jutsu to heal incurable diseases, which would make him a famous doctor not just in his village but across the ninja world.
In this fanfiction, Naruto could be a doctor who specializes in treating ninja - related injuries. Since he has experienced many battles himself, he has a unique understanding of the types of wounds and traumas that ninjas endure. He might develop new rehabilitation techniques for ninjas who have lost their limbs or chakra - using abilities. His kind heart and determination would make him a beloved doctor, always going the extra mile to save his patients.
One interesting storyline could be the Doctor using his time - traveling abilities to visit different eras in the Avengers' timeline and help them prevent disasters that they otherwise couldn't. For example, he could go back to the events of the first Avengers movie and use his knowledge to stop Loki's plan more efficiently.
Another storyline could involve Naruto's daughter being sent on a special mission that is related to a mystery from Naruto's past. Maybe she discovers some secrets about her father's early days that were never known before. This could lead to her having to make some tough decisions about how to handle this newfound knowledge.
One interesting storyline could be a crossover where Naruto's world of ninjas collides with Seras' vampiric world. Maybe Naruto is on a mission in a strange land and stumbles upon Seras. They could team up to fight a common enemy that threatens both their worlds.
Well, in some Naruto sickle fanfiction, there might be a plot where the sickle is a cursed weapon. It might bring misfortune to whoever wields it, but the main character has to find a way to break the curse. Maybe it was used in a past war and has a dark history. Also, a story could revolve around a young ninja who inherits a sickle from a fallen hero and has to live up to the legacy while also uncovering the secrets of the sickle.
One interesting storyline could be a ninja who discovers a pair of magical headphones in the Naruto world. These headphones might enhance their chakra control when they wear them while training. For example, they could hear the natural flow of chakra in the environment, like the rustling of leaves representing wind chakra or the gurgling of a stream for water chakra.
There could be a storyline where the 11th Doctor and the OC find themselves in a parallel universe. In this universe, things are very different from what they are used to. They have to figure out how to get back to their own universe while also dealing with the strange things in this new one. Along the way, they might meet alternate versions of their friends or enemies, which adds to the complexity and excitement of the story.
A great storyline might be a time - travel fanfiction where Naruto and Tsunade are sent back in time. They have to figure out how to get back to their own time while also changing certain events in the past that could have a major impact on the future of the ninja world. This would allow for a lot of character development and exploration of the Naruto universe's history.
One interesting storyline could be a crossover where Naruto visits the world of Rossweisse. He could introduce his ninja skills to her world and they team up to face a common threat. For example, a powerful dark magic user who is causing chaos. Naruto's speed and combat skills combined with Rossweisse's knowledge of magic would make for an exciting adventure.
One interesting storyline could be about Naruto having a different power origin. For example, instead of being the host of the Nine - Tails, he might gain his power from an ancient sage. This could change the whole dynamic of his character development and relationships in the story.
A possible storyline is that Yoruichi discovers a way to travel to the Naruto universe due to some strange rift in the dimensions. She meets Naruto when he is still a young outcast in the village. Yoruichi, seeing his potential, decides to help him secretly. This leads to Naruto developing some new and unexpected abilities, which confounds his teachers and makes him an even more formidable ninja as he grows up.