One idea could be exploring the Four Tails' backstory more in - depth. Maybe it has a connection to an ancient ninja clan that was long forgotten. Another is a story where the host of the Four Tails has to team up with an unexpected ally to control its power.
In some fanfictions, a cool plot could be that the Four Tails has a unique ability that no one knew about. For example, it can create portals to different dimensions. And the story could revolve around the main character trying to use this ability for good, while others want to misuse it. Also, a plot about the Four Tails' relationship with other tailed beasts in a more personal way, like they have a secret communication system, would be interesting.
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.
Perhaps in the fanfiction, the Zero Tails is a manifestation of the negative emotions of the ninja world as a whole. A group of young ninjas discover this and they try to find a way to purify the Zero Tails. They seek the help of old sages and learn ancient jutsu to attempt this purification, which could lead to a battle against those who want to keep the Zero Tails as a weapon of mass destruction.
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, in this fanfiction, it might be that Naruto's transformation into the four - tails form reveals some hidden secrets about the Nine - Tails' origin. This could lead to a whole new adventure as he tries to uncover more about it. Also, perhaps the four - tails form has a different set of abilities compared to what we've seen before, which makes for exciting battles and challenges for Naruto to overcome.
Well, a possible plot for a 'naruto with tails fanfic' might involve Naruto using his tails to travel to different dimensions. In these dimensions, he could encounter alternate versions of his friends and enemies. He might have to use the unique abilities of his tails to find his way back home. Or perhaps his tails start to develop a mind of their own and he has to work with them rather than against them to become stronger. Maybe he discovers that his tails hold the key to unlocking a long - lost prophecy related to the Hidden Leaf Village.
One plot idea could be Naruto and the Nine - Tails having a spiritual conversation that changes Naruto's perception of their relationship. For example, the Nine - Tails could reveal some secrets about the Uzumaki clan that Naruto didn't know before. Another idea is that they could team up in a unique way to face a new and powerful enemy in the Hidden Leaf Village. Maybe there's a dark force that can only be defeated by their combined power and a special bond they form.
One idea could be the six - tails jinchuriki's struggle to control the power. For example, they constantly have to battle the inner urge of the six - tails to go on a rampage. Another plot could involve the jinchuriki being hunted by an evil organization that wants to extract the six - tails' power for their own malicious use. They would then have to fight and outwit this organization while also dealing with the social ostracism that often comes with being a jinchuriki.
Well, a cool plot for Naruto six - tails form fanfiction might be about time travel. Naruto accidentally travels back in time while in six - tails form. He then has to figure out how to hide his form from his younger self and the people in the past. At the same time, he could use his knowledge from the future and the power of the six - tails to prevent some great disasters from happening in the past, which would change the future in unexpected ways.
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.