One interesting 'Nagato trains Naruto' fanfiction could be where Nagato imparts his unique skills and knowledge about the Rinnegan to Naruto. This might include training Naruto in the various abilities associated with the Rinnegan, like the Six Paths techniques.
You can try searching on popular fanfiction websites such as FanFiction.net or Archive of Our Own (AO3). These platforms have a large collection of Naruto fanfictions, and by using the search terms 'Nagato trains Naruto', you may be able to find relevant stories.
In some fanfictions, Asuma might train Naruto in stealth and strategy. For example, he could set up mock battles where Naruto has to outwit his opponents using clever strategies rather than brute force. This type of training would add a new dimension to Naruto's ninja skills.
There could be a fanfiction where Kakuzu trains Naruto in dealing with his chakra in a more efficient way. Since Kakuzu has unique abilities related to his chakra and his multiple hearts, he could pass on some knowledge to Naruto about conserving and using chakra better. For example, he might show Naruto how to distribute chakra evenly throughout his body for faster movement or stronger attacks.
One interesting fanfiction could be 'Minato's Training Legacy'. In this, Minato imparts his unique jutsu knowledge to Naruto in a very detailed and creative way. It might show Minato teaching Naruto how to better control his chakra for the Rasengan, just like he did in the original series but with more in - depth exploration.
One interesting 'Akatsuki trains Naruto' fanfiction could be one where the Akatsuki members teach Naruto unique jutsu. For example, they might show him some dark - side - influenced ninjutsu that he can then adapt to his own style. Another could involve them training Naruto in stealth and espionage, skills that the Akatsuki are known for.
One interesting fanfiction could be where Iruka trains Naruto in advanced ninjutsu techniques that are not taught in the regular academy. This could lead to Naruto becoming even stronger at a faster pace and having unique skills in battle.
I've heard of 'Female Nagato in Naruto's World'. In this fanfiction, female Nagato is inserted into Naruto's regular adventures. Naruto is initially curious about her and her different perspective. They end up on missions together, and through those shared experiences, Naruto begins to see her in a new light. Their bond grows as they support each other in battles and also in understanding the complex politics and power struggles within the ninja villages.
There could be a fanfiction where Danzo trains Naruto after realizing that Naruto's unique chakra and ability to make friends could be harnessed for the Root's purposes. However, Naruto being Naruto, he would try to influence Danzo to use these skills in a more positive and moral way, leading to an interesting dynamic between the two characters.
One popular 'fox god trains naruto' fanfiction might be 'The Fox God's Guidance'. In this story, the fox god could teach Naruto unique and powerful jutsu that he might not learn otherwise. It often focuses on Naruto's growth under the fox god's mentorship, exploring his potential in new ways.
One interesting 'Hana Trains Naruto' fanfic could be where Hana uses her unique skills to train Naruto in tracking and stealth. For example, she might take him into the forest and teach him how to follow the faintest of scents, just as she does with her ninja dogs.