The most unexpected sensei could be Hinata's father, Hiashi. Hiashi is a very traditional and strict ninja. If he were to train Naruto, he would likely enforce a lot of discipline and propriety. He could teach Naruto some of the Hyuga clan's secrets, like how to better use his chakra control for precise attacks. This would be a huge departure from Naruto's normal, more free - spirited training.
Probably Tenten's sensei, Might Guy. It would be unexpected because Naruto is not really associated with the more physical and taijutsu - focused training that Guy is known for. But if Guy were Naruto's sensei, he would push Naruto to his limits in terms of physical strength and endurance. Naruto might also learn some really flashy taijutsu moves that are completely different from his normal combat style.
I think Orochimaru would be the most unexpected sensei. Usually, he's seen as a villain, but in a fanfiction, if he were to train Naruto, it would be extremely unexpected. He has a vast knowledge of jutsu, especially forbidden ones. He could teach Naruto some very powerful and unique abilities, but at the same time, Naruto would have to deal with Orochimaru's morally ambiguous nature.
Kurenai might be a good sensei for Naruto's different team. Her expertise in genjutsu would be valuable. She could help the team develop their skills in this area, especially if the new team members have some potential in genjutsu. Kurenai is also very perceptive, which would be great for guiding Naruto and his new teammates through difficult situations.
In the fanfiction, Naruto's new sensei could be a mysterious figure who has ties to the Sage of Six Paths. This person might have been waiting for the right time to appear and train Naruto. They could possess knowledge about the origin of chakra and how to fully unlock Naruto's power. It could also be someone who was once an enemy but has now changed their ways and wants to use their skills to train Naruto for the greater good of the ninja world.
There's a chance that Naruto's new sensei could be a self - taught ninja who has developed their own unorthodox style. This person sees Naruto's ability to think outside the box and wants to refine that in him. They could introduce Naruto to a new way of looking at chakra control and combat strategies that are completely different from what he has been taught so far.
One possibility could be that Sakura is under Tsunade's tutelage while Naruto is trained by Jiraiya. This would lead to different styles of training. Sakura would focus more on medical ninjutsu and precise chakra control like Tsunade. Naruto, with Jiraiya, would learn more about summoning jutsu and unpredictable combat styles. Their growth paths would diverge in interesting ways, affecting how they interact with each other and their roles in the village.
Tenten would also be an interesting choice. She could focus on weapon - based combat training for Team 7. Since she has extensive knowledge of all kinds of weapons, she could introduce new and unique weapon techniques to the team.
Naruto is often paired with Ebisu Sensei in fanfiction. Since Ebisu was assigned to train Naruto at one point, many fanfictions build on that relationship, showing how Naruto grows under his tutelage and how Ebisu has to adapt to Naruto's unorthodox ways.
Well, it could be the children of his friends. For instance, Boruto could be one of his students, and Naruto could use his own father - son relationship with Boruto as a teaching tool, sharing stories of his own father to inspire Boruto. Another student could be Sarada, Sasuke's daughter. Naruto could teach her some of the skills he learned from Jiraiya, passing on that knowledge.
Anko's a bit of a rebel in some ways. This could encourage Naruto to think outside the box when it comes to ninja tactics. He wouldn't be so bound by the traditional ways. For example, he might come up with new ways to combine his Rasengan with other jutsu based on Anko's unorthodox thinking. Also, her somewhat edgy personality could make Naruto more street - smart and less naive in the ninja world.
Naruto could use his own life story as a teaching tool. He could tell his students about how he was an outcast as a kid because of the Nine - Tails inside him, and how he overcame all the difficulties. This would inspire his students to keep going no matter what obstacles they face. He would also be very passionate about teaching them new jutsu and would probably show them some of his own unique techniques like the Rasengan.
If they had different sensei, their relationship could become more competitive. For example, if Sakura's sensei focused on making her a top - tier medical ninja quickly and Naruto's sensei was pushing him to master new powerful jutsu, they might compete to prove who is more valuable to the village.