One possible plotline could be Tsunade teaching Naruto more about medical ninjutsu. Since she is a great medical ninja, she could pass on her knowledge to Naruto, which would add a new dimension to his skills. Another aspect could be her guiding Naruto in leadership, as she is the Hokage. This might help Naruto in his future role as a leader in the village.
Perhaps the fanfic could explore Tsunade training Naruto in a more intense and personalized way. She has her own unique fighting style and vast combat experience. She could train Naruto to better control his chakra, especially when using the Nine - Tails' power. Also, she might introduce Naruto to some of her old comrades or contacts, opening up new adventures and opportunities for Naruto to grow both as a ninja and as a person.
Perhaps in the fanfic, Futa is a new character in the Naruto world who has some sort of connection to Tsunade's past. Naruto gets caught in the middle of their relationship. It could involve Futa having some secrets that Tsunade is desperate to know, and Naruto helps in uncovering those secrets while also growing as a ninja himself.
A plotline could revolve around Sakura trying to understand Tsunade's past more deeply. Tsunade might be reluctant at first, but as they work together more closely, she starts to open up. This could lead to Sakura learning important life lessons from Tsunade's experiences, like how to deal with loss and keep going. They could also get into a situation where they have to use their combined medical and combat skills to save a group of injured ninjas.
One possible plotline could be that Tsunade and Naruto go on a dangerous mission together and Tsunade has to protect Naruto at first, but then Naruto's growth allows him to contribute significantly. Another could be that Tsunade is teaching Naruto some special medical jutsu, and they have a mentor - mentee relationship throughout the story.
Another plotline might be that Tsunade is affected by some kind of dark magic or genjutsu that makes her turn against Naruto. Naruto, realizing it's not really Tsunade's fault, still has to fight her to try and break the spell. He could call upon his friends for help, but in the end, it's his determination and his bond with Tsunade that helps him reach her and break the control.
One possible plotline could be that Naruto leaves with Tsunade on a mission to find a rare herb that is said to have the power to heal any wound. Along the way, they face various enemies who also want the herb for their own malicious purposes. Naruto's skills and Tsunade's wisdom would be put to the test as they battle their way through.
In a Naruto - raises - Gaara fanfiction, Naruto could help Gaara deal with his inner demon. Gaara has had a tough time controlling Shukaku, his tailed beast. Naruto, who has also had to deal with the power of the Nine - Tails, could offer advice and support. He might teach Gaara some of the meditation techniques he used to keep the Nine - Tails in check. This would lead to Gaara having better control over his powers and becoming a more stable and powerful shinobi. Also, Naruto could help Gaara improve his relationship with the people of Suna. Given Naruto's charm and ability to make friends, he could show Gaara how to win the trust and love of his own villagers.
One possible plotline could be Naruto teaching Anko some of his unique ninja skills. Since Naruto has a lot of experience with Rasengan and other techniques, he could pass on some knowledge to Anko, who might be struggling with her own skills development. Another aspect could be Naruto helping Anko overcome some personal traumas. Maybe Anko has some past experiences that are holding her back, and Naruto's positive attitude and his own history of overcoming difficulties could inspire her. Also, they could go on missions together where Naruto's quick - thinking and Anko's more experienced knowledge of certain areas combine to make them a great team.
One possible plotline could be Bellatrix trying to mold Harry into a dark wizard. She might use her knowledge of the Dark Arts to teach him, but Harry resists. Another could be that Bellatrix starts to have a change of heart while raising Harry and begins to question her loyalty to Voldemort. Maybe she sees something in Harry that reminds her of a better part of herself.
A possible plotline could be about family secrets. Tsunade might reveal some long - hidden family secrets to Naruto that change his perspective on his family and his place in the village. For example, she could tell him about a special kekkei genkai that runs in the family that he might inherit.
One possible plotline could be Naruto feeling extremely lost and having to find his own way to become stronger without their guidance. He might start to question his own worth and abilities, but then he could meet new allies who help him realize his true potential on his own. For example, he could encounter some other outcast ninja who have their own unique skills and together they form a new kind of ninja team that challenges the traditional ways of the ninja world.