Well, perhaps Naruto finds himself in a world where the Laguz are being oppressed. He decides to fight for them because he sees their struggle as similar to that of his own village. He could use his ninja skills to protect them from any threats, be it other powerful groups or some sort of dark force that wants to take advantage of the Laguz.
It could be a group of power - hungry humans who see the Laguz as a resource to be exploited. They might want to use the Laguz's unique abilities for their own gain, like using their strength in labor or their magical abilities for warfare.
It could be a new group of rogue ninjas who have a vendetta against Konoha. They might be led by a powerful and cunning ninja who has a personal grudge against Naruto or the village in general.
In many fanfictions about Naruto fighting Sasuke during the Chunin Exams, it often showcases their intense rivalry. One common aspect is the display of new jutsus that they might have developed secretly. For example, Naruto could have a new form of the Rasengan, and Sasuke might have evolved his Chidori in some unique way. This makes the fight more exciting as it goes beyond what we saw in the original series.
In this fanfiction scenario, Naruto would bring his own unique fighting style. He's got his shadow clones and Rasengan. Sasori is a tough opponent with his puppet army. Naruto might struggle at first to deal with the puppets' various attacks. But with his determination and quick thinking, he could find a way to get close to Sasori and use his Rasengan. It would be an intense battle, different from the one Sakura had with Sasori, as Naruto has a completely different set of skills and strategies.
Naruto's Rasengan would be a key skill. He might start with a basic Rasengan and as the fight progresses, he could develop it into a more powerful form like the Big Ball Rasengan. His shadow clone jutsu would also play a major role. He could create a large number of clones to surround Tsunade, confusing her and making it difficult for her to target the real Naruto.
In this fanfiction, the plot might involve Naruto being tricked by an evil force into believing that the Fourth Hokage has some dark secrets. So he decides to fight him. It could also be a scenario where Naruto enters a different dimension where the Fourth Hokage is being controlled by an outside power, and Naruto has to free him by fighting. And during the fight, Naruto discovers new things about his father and his own abilities.
Perhaps in the fanfiction, Naruto discovers a hidden secret about his family that gives him an edge in his fight back. For example, he might find out that his family had a special connection to a powerful force or technique, and he uses this knowledge to gain strength and take on his foes. This could involve him having to train hard to unlock this potential within himself.
In such a fanfiction, Naruto could potentially win by using his new Sage of Six Paths powers to their fullest. He might be able to overpower Madara's Rinnegan abilities. For example, Naruto could use his massive chakra reserves to create countless shadow clones and overwhelm Madara in a battle of attrition.
In a fanfiction where Naruto fights his parents, it could be a really emotional and complex situation. Maybe it's a result of some sort of mind - control or misunderstanding. Naruto, being a strong - willed character, would likely hold back at first, not wanting to harm them. His parents, on the other hand, might be acting out of some forced obligation or false belief. It could lead to a battle that ultimately ends with Naruto finding a way to break whatever spell or falsehood is causing the rift, and they'd have a tearful reunion.