Sasuke is often a popular character in these fanfics. His own stint as a sort of rogue ninja makes him a natural fit. Also, Orochimaru, who was a rogue ninja for a long time, is frequently included. He has a lot of mystery and power associated with him.
Kakashi could also be the main character in a different take on 'naruto rogue ninja fanfiction'. Imagine if for some reason, Kakashi was framed as a rogue ninja. He would have to use his intelligence and combat skills to clear his name while also dealing with the challenges of being an outcast. He might even discover some dark secrets about the Hidden Leaf Village in the process.
The Leaf Village authorities could be the main antagonists. Since Naruto is now considered a rogue, they would be the ones trying to hunt him down. They might see him as a threat to the village's stability and security.
Well, one interesting plot could be Naruto's struggle to survive in a world that now sees him as a rogue. He might have to constantly evade capture from his former friends and allies. Another could be his journey to find out who framed him as a rogue in the first place.
One interesting plot could be a rogue ninja who discovers a hidden power within themselves that was suppressed all along. This new power makes them a target for both their former village and other rogue elements. Another plot might involve a rogue ninja forming an unlikely alliance with other outcasts to take on a greater evil that threatens the ninja world.
In a 'naruto becomes a rogue ninja fanfic', it could start with Naruto being ostracized by the village due to his growing power which some elders fear. They try to suppress him, and Naruto, feeling betrayed, decides to leave and become a rogue ninja. He then might go on a journey to find a new place where he can be accepted for who he is, and along the way, he could meet new allies and enemies alike. He may also develop new jutsu away from the traditional teachings of the village.
One idea could be a rogue ninja who was once a close friend of Naruto but turned due to a misunderstanding. They could have unique powers and be on a mission to prove their own version of justice.
Well, one possibility is that Naruto feels betrayed by the Hidden Leaf Village. Maybe they wrongly accused him of a serious crime. So, he decides to go rogue. He could then start traveling alone, using his skills to survive and avoid capture. He might also meet other outcasts who understand his situation.
It could be a group of rogue ninja who have a vendetta against Naruto. They might see his new status as a rogue as an opportunity to take him down. Maybe they were once defeated by Naruto when he was in the village, and now they want revenge. Also, there could be some hidden shinobi clans within the village who oppose Naruto's new path and try to stop him for their own reasons, like protecting the village's reputation or their own power within the village.
Well, his relationship with the village as a whole would be one of enmity. But on an individual level, some of his friends might secretly support him. Naruto would likely be more cautious about trusting new people. His connection with the other jinchuriki might become stronger as they can relate to his situation of being an outcast. His relationship with Kakashi - sensei would be filled with conflict. Kakashi would have to balance his duty to the village and his feelings for Naruto, who he has trained and cared about.