Well, a great plot for 'Naruto Different Sensei Fanfiction' would be if Naruto was taught by Jiraiya's sensei, Hiruzen Sarutobi. Sarutobi could pass on some ancient and powerful jutsu to Naruto that Jiraiya didn't know. He could also instill in Naruto a deeper understanding of the village's history and politics. Also, Naruto could be trained by Anko Mitarashi. She has a wild and unorthodox style, which would make Naruto's training very different. He might learn some really unique snake - related jutsu from her.
In a 'Naruto Different Sensei Fanfiction', Naruto could be under the tutelage of Minato's sensei, Jiraiya. But in this version, Jiraiya focuses more on Minato - style combat and space - time ninjutsu from the start. This would make Naruto a very different kind of ninja early on. Or, imagine Naruto being trained by Shikamaru's father, Shikaku. Shikaku is known for his intelligence. He would teach Naruto how to use his brain more in combat, perhaps introducing new strategies and battle formations that Naruto has never considered before.
One idea could be Naruto being trained by Kakashi's father, Sakumo. Since Sakumo was known for his skills, he could teach Naruto some unique jutsu and a different perspective on being a ninja. Another plot could involve Naruto being mentored by Tsunade's younger brother Nawaki. It would change Naruto's development as Nawaki might have his own special way of teaching. Maybe he'd focus more on medical ninjutsu combined with combat skills.