One idea could be that the character with the Sharingan is banished due to false accusations of using its power for evil. He then has to journey alone, facing challenges and learning to control his power in new ways. Maybe he meets a group of outcasts who he befriends and together they fight against the unjust system that banished him.
A possible plot could be that Naruto is given a temporary Sharingan by an ancient Uchiha spirit. With this Sharingan, he starts to see the world in a different way, and he realizes that there are hidden threats in the ninja world that only the Sharingan can detect. He then embarks on a journey to find out more about these threats and how to stop them. Another plot could be that Naruto meets an Uchiha survivor who teaches him how to use the Sharingan in a way that no one else has thought of. This new way of using the Sharingan could help Naruto in his fight against the Akatsuki. And there could also be a plot where Naruto's Sharingan evolves in a unique way because of his Uzumaki heritage.
One idea could be a story where Naruto somehow gains the Golden Sharingan. He could use its unique powers to see through genjutsu more easily and also have enhanced perception in battle. For example, he might be able to predict his opponents' moves better. Another plot could involve Naruto using the Golden Sharingan to unlock a new form of his Rasengan, perhaps one with the ability to disrupt an enemy's chakra flow on a deeper level. Or, it could be a story where Naruto has to team up with a character who has knowledge of the Sharingan to fully understand and control the Golden Sharingan's powers.
One idea could be a story where the main character, who has the Eternal Sharingan, has to face a new and powerful enemy that can manipulate time. With the power of the Eternal Sharingan, the character has to find a way to break the enemy's time - based attacks and defenses. Another plot could revolve around a character with the Eternal Sharingan trying to uncover long - lost secrets of the Uchiha clan that are hidden deep within the Sharingan's powers. Maybe there are ancient jutsu or prophecies that only the Eternal Sharingan can unlock.
One idea is that an enemy targets Kakashi's Sharingan and Naruto has to protect it. Along the way, Naruto learns more about the Sharingan's capabilities and how to use it against the enemy. This would be a great opportunity for Naruto to grow as a ninja and for their friendship to deepen.
One idea could be a character from RWBY obtaining the Sharingan and using its abilities in combat. For example, Ruby could get the Sharingan and combine its precognitive abilities with her own speed, making her an even more formidable fighter.
One idea could be that Hatake Kakashi somehow transfers his Sharingan to Naruto in a dangerous mission. This would give Naruto new abilities and a whole new set of challenges to face. He'd have to learn to control the Sharingan quickly while also dealing with the enemies who might target him specifically for it.
One idea could be exploring a different origin for the Mangekyou Sharingan. For example, what if it was related to an ancient Uchiha pact with a hidden spirit? Another could be a story where a non - Uchiha character somehow gains the ability to use the Mangekyou Sharingan and has to deal with the consequences. Or perhaps a fanfiction where the Mangekyou Sharingan has additional powers that are not shown in the original Naruto series, like the ability to time - travel.
A possible plot could involve the banished mercenary being from a long - lost clan. The reason for his banishment was a false accusation by a rival clan. As he wanders the Naruto world as a mercenary, he discovers clues about his clan's true heritage and power. He then uses his skills as a mercenary to gather allies and resources to prove his clan's innocence and restore its honor. Along the way, he crosses paths with Naruto and his friends and they either help or hinder his quest depending on the situation.
One plot idea could be Naruto being banished to the world of One Piece. He could join the Straw Hat Pirates and use his ninja skills in new and exciting ways. For example, his shadow clone jutsu could be used for various tasks on the ship. Another idea is that he gets banished to the Bleach universe. He might learn about Soul Reapers and Hollows, and his chakra could be seen as a unique form of spiritual energy there. Maybe he could even train with the Soul Society to become stronger.
One idea could be that Naruto and Tenten are banished due to a false accusation of plotting against the village. They then have to prove their innocence while on the run. They might encounter old enemies who have also been exiled and form an unlikely alliance to clear their names.