One idea could be Naruto exploring the true origin of the Nine - Tails within his own family history. Maybe his ancestors had a special connection to the Nine - Tails that was long forgotten.
A third plot idea could be that the Nine - Tails starts to have a mind of its own and tries to influence Naruto in a negative way. Naruto has to struggle with this internal conflict while also dealing with external threats. He would have to find a way to either subdue the Nine - Tails' negative influence or come to some sort of understanding with it.
A possible plot is that Naruto's fox ears and nine - tails features are initially a source of fear and misunderstanding among the villagers. But as he starts to master these traits, he uses them to protect the village in unique ways. For instance, his nine - tails can create a powerful shield around the village when it's under attack, and his fox ears help him to coordinate the defense more effectively.
One idea could be Naruto having a unique connection with the Nine Tails that allows him to access new forms not in the original series. For example, a form that combines his human features with more fox - like aspects in a more aesthetically pleasing and powerful way.
One idea could be a fanfiction where Naruto has to temporarily transfer the Nine - Tails' power to a fellow ninja to save the village. This would create an interesting dynamic as the other ninja has to quickly adapt to the power and the responsibility that comes with it.
Well, a great plot could be about Naruto losing control of his Nine Tails Cloak in a more psychological way. Instead of just being overpowered physically, he starts to have nightmares and visions related to the Nine Tails while in the cloak. This could lead to a journey of self - discovery where he has to face his inner demons as well as the power of the cloak. Also, a story where the Nine Tails Cloak can be used to travel through different dimensions or time periods would be really interesting.
One idea could be Naruto using the Nine - Tails' power to travel to different dimensions and encounter versions of his friends with different personalities. Another could be him training with the Nine - Tails to create new and unique jutsu that no one has ever seen before. Maybe he uses the power to go back in time and change certain events in the ninja world's history for the better.
Well, there could be a fanfiction where the Nine - Tails Chakra has a mind of its own and starts to communicate with Naruto in a more complex way. It could show him visions of the future of the ninja world and guide him to make choices that are different from what he would have done otherwise. This could lead to new alliances and a completely different path for Naruto and his friends in the story.
For a 'naruto of the nine tails fanfic', a great plot could involve the nine - tails sharing its ancient memories with Naruto. These memories could give Naruto insights into the history of the ninja world and new ways to use his power. Additionally, a plot where the nine - tails starts to develop its own emotions and opinions that conflict with Naruto's, leading to an internal struggle for Naruto, would be really interesting.
Perhaps in the fanfiction, the baby nine - tails gets separated from Naruto for a while. During this time, it has to fend for itself in a world that fears it. It could meet other friendly or hostile creatures and have various adventures before reuniting with Naruto.
Well, a cool plot might be that Naruto uses the Nine - Tails to travel to different dimensions. He could explore places that were previously unknown and discover new powers or allies there. Also, in the fanfic, he could use the Nine - Tails' chakra to heal the land that was damaged by previous battles. This would show his growth not just as a fighter but also as a protector of the village and its surroundings.
One idea could be exploring the origin of the Ten - Tails in a different light. Maybe it was created by an ancient civilization for a noble purpose that got corrupted over time. Another could be a story where a young ninja discovers a hidden power within the Ten - Tails and has to learn to control it without being consumed by its dark energy.