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.
Some fanfics may explore the idea that the Kyuubi's obsession is due to Naruto's unique spirit. So, it might start to manipulate events around Naruto to make him stronger faster. For example, it could draw out Naruto's enemies in a way that forces Naruto to quickly level up his skills. It could also be that the Kyuubi, out of its obsession, tries to change Naruto's view on the concept of power and how it should be used, which could lead to some really interesting moral and ethical dilemmas for Naruto.
One plot idea could be that the fem Kyuubi has a human form and she and Naruto have to go on a journey to find a way to restore balance in the ninja world that has been disrupted by some dark force. Along the way, they gradually fall in love as they face challenges together.
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.
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.
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.
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.
One idea could be exploring the bond between Naruto and the Kyuubi in a new way. For example, they could have a shared dream where they are in a strange, alternate world and have to work together to find a way back. Another plot could involve Naruto using the Kyuubi's power to save a village from a new, powerful enemy that no one else can defeat. And a third could be about the Kyuubi revealing a long - lost secret about Naruto's family that changes his perspective on his own powers.
One interesting idea could be the unique ways Naruto combines his skills with the power of the Kyuubi cloak. For example, he might develop new jutsu that are only possible when in the cloaked state. Another idea could be how the cloak affects his relationships with other characters. Some might be in awe of his new power, while others could be a bit fearful.
One idea could be a story where Naruto discovers a hidden power within the Kyuubi suit that allows him to time - travel. He could use this power to prevent certain tragedies in the Naruto universe. Another idea is that the Kyuubi suit starts to have a mind of its own and Naruto has to learn to cooperate with it in a new way, like sharing thoughts and strategies directly.
One idea could be that the power transfer is not straightforward. Maybe Kyuubi's power starts to change Naruto's appearance in unexpected ways, like giving him fox - like features that he has to learn to hide. This could lead to some comical and also tense moments as he tries to keep it a secret from his friends.