A really interesting plot could be that the Kyuubi bloodline in Naruto starts to have an effect on his relationships. Some people in the village might be afraid of him now that they know he has this powerful bloodline. On the other hand, some might see him as an even greater asset. Naruto then has to deal with the social implications while also training to control the new powers that come with his Kyuubi bloodline. He could also find out that there are other ninja out there with a similar bloodline from other tailed beasts, and they come together to form a unique group.
One idea could be exploring the relationship between Naruto and the Kyuubi no Kitsune in a more spiritual way. Maybe Naruto can have dreams where he actually communes with the fox spirit and gains new insights about his powers. Another plot could involve a situation where the Kyuubi's powers start to merge with Naruto in unexpected ways, causing him to develop new abilities that he has to learn to control quickly.
One idea could be that the female Kyuubi has the ability to transform into a human form and she becomes Naruto's secret protector. She uses her powers subtly to keep him out of harm's way while he's on his missions, and Naruto starts to notice strange things happening but doesn't know it's her at first.
The plot could involve the child being sought after by various ninja clans who want to use the power of the Kyuubi within the child for their own purposes. The child, with Naruto's teachings, resists and tries to find a way to use the power for the good of the village. Maybe the child discovers a new form of chakra control that combines Naruto's Uzumaki heritage and the Kyuubi's power.
Perhaps in the fanfic, the hypnosis bloodline allows the user to enter people's minds and change their memories. The story could be about a character who uses this ability to rewrite the past of a village that has been corrupted by an evil force. However, they soon realize that changing memories has unforeseen consequences and they have to find a way to fix the mess they've created.
One interesting plot could be the discovery of an ancient prophecy that states a person with a specific Zanpakuto bloodline will be the key to saving the Naruto world from an impending doom. This person is initially unaware of their bloodline and must go on a journey of self - discovery. As they do, they learn about the power of their Zanpakuto and how it relates to their bloodline. They face numerous challenges, including battles with other powerful ninjas who want to use the prophecy for their own gain.
One idea could be a character with a devil bloodline being initially shunned in the Hidden Leaf Village but then proving their worth in a major battle. For example, they could use their unique devil - like abilities, such as enhanced speed and strength, to turn the tide against a powerful enemy.
One idea could be a story where the main character discovers their Furyan bloodline late in their ninja training. This newfound power could cause conflict with their village at first as they struggle to control it. Then, they go on a journey to learn about their bloodline's origin and meet other characters with similar powers.
One interesting plot idea could be exploring how Minato's relationship with the Kyuubi affects Naruto. For example, Naruto discovers some hidden memories of Minato's encounter with the Kyuubi that give him new powers or insights. Another idea is a story where Minato has to return from the afterlife briefly to help Naruto control the Kyuubi's power more effectively. Maybe there could also be a plot where the Kyuubi has a change of heart due to Naruto's kindness and decides to reveal secrets about Minato that no one else knew.
Well, in some fanfics, the Kyuubi's obsession might result in it influencing Naruto's chakra in a unique way. This could lead to Naruto developing new and unexpected jutsu. Also, the Kyuubi could be so obsessed that it tries to merge with Naruto in a different way than just lending its power, like actually becoming one entity with Naruto but still maintaining their individual consciousnesses to some extent.
Maybe in the fanfic, Naruto gets injured while protecting the Fem Kyuubi from some other powerful force. This act of self - sacrifice makes her realize her deep love for him. Then, they start to train together, not just for power but also to strengthen their bond, sharing their secrets and fears during the process.