Here's an idea. In the fanfiction, Naruto accidentally enters a parallel universe where all the characters have different personalities. For instance, Sasuke could be a carefree joker instead of the brooding avenger. Naruto has to find a way back to his own universe while also dealing with the strange new versions of his friends. Another plot could be that Naruto is cursed with a strange illness that makes him lose his chakra bit by bit. He has to find a cure while still protecting the village. And then there could be a story where Naruto discovers a new type of chakra that no one in the Naruto world has ever seen before and has to learn how to control it.
Well, you could do a fanfiction where Naruto has a long - lost twin. This twin was separated at birth and raised in a different village with different values. When they meet, there's a clash of ideals, but also a chance for Naruto to understand a different perspective. Or, consider a plot where Naruto is framed for a serious crime in Konoha. He has to go on the run and prove his innocence while also uncovering a conspiracy within the village. Also, a story about Naruto training in a secret, forbidden dimension full of powerful and ancient chakra could be really cool.
One interesting plot idea could be a time - travel story. For example, Naruto is sent back in time to the era of the First Hokage. He could use his knowledge of future jutsu and events to change things for the better in the past. Another idea is a story where Naruto discovers a hidden clan within Konoha that has a unique and powerful Kekkei Genkai. He then has to help this clan gain acceptance in the village. A third idea might be a story where Naruto is turned into a different creature, like a cat or a fox, and has to find a way to turn back while still dealing with the normal threats to the village.
One idea could be that Neji discovers a new hidden power within Naruto that he helps Naruto master. This could lead to them having to face a new, powerful enemy together.
A plot idea could be that Naruto discovers a new, ancient form of chakra that has been lost for centuries. He then has to train to master this chakra while also dealing with the political implications within the Hidden Leaf Village. Some elders might be against him exploring this new power for fear of the unknown, but Naruto, being Naruto, is determined to master it for the good of the village.
One idea could be that the events of 9/11 somehow influence the Hidden Leaf Village. For example, they might tighten security and Naruto could be part of a new team in charge of protecting the village from potential outside threats inspired by the real - world event. Another plot could involve characters from Naruto trying to understand the concept of such a large - scale tragedy and how they can prevent similar things in their own world.
A really interesting plot could be a time - travel fanfiction. Naruto and Temari are sent back in time to a crucial moment in the history of their villages. They have to work together to make sure the events unfold in a way that doesn't change the future too drastically, but also helps to prevent some of the darker events that occurred in their past.
One idea could be that Noodlehammer Naruto has some unique jutsu related to his 'noodlehammer' concept that he teaches to the original Naruto. This could lead to new ways of fighting enemies in the Naruto world. Another plot could involve them teaming up to face a powerful new villain who is immune to normal ninja techniques but is vulnerable to the strange powers of Noodlehammer Naruto.
One plot idea could be exploring her relationship with Minato before Naruto was born. Maybe she had some premonitions about the future and tried to prepare Minato in some way. Another idea is that she could have had a secret jutsu or power that she passed on to Naruto without anyone knowing. And a third idea could be her having a role in the shinobi world that was cut short by her untimely death.
Perhaps the OC is a healer who is the only one who can keep Naruto's body stable when he overuses his Rinnegan. Their relationship starts as a necessity but then develops into a deep friendship or more. They get involved in a conflict where Naruto has to use his Rinnegan to save the OC's clan from destruction, and in the process, they learn more about the secrets of the Rinnegan and their own destinies.
A great plot could involve the female Naruto being sent on a diplomatic mission to another village. There, she discovers a conspiracy against the Hidden Leaf Village and has to use her wits and ninja skills to expose it and prevent a war. Along the way, she also forms unexpected friendships with some of the villagers from the other village, which helps her in her mission.
A really interesting plot could be a tournament in which both Naruto characters and Pokegirls participate. They have to fight against each other using their respective skills. It would be a test of strategy and power, and also a great opportunity for character development as they learn from one another's fighting styles.
One idea could be that Naruto somehow gets transported to the world where Tiamat exists. He has to use his ninja skills to survive in a completely different and magical realm. Maybe he teams up with local heroes to face a threat that Tiamat also has an interest in.