A really interesting plot in Hokage Naruto time travel fanfiction could be Naruto traveling to a time during a great war in the past. He could use his skills and knowledge from the future to turn the tides of the war. Maybe he would form unexpected alliances with past ninja, or he could introduce new strategies that were developed in his time. This would not only change the outcome of that war but also have a huge impact on the future of the ninja world.
One idea could be the Nanadaime Hokage (Seventh Hokage Naruto) traveling back in time to his younger self's era. He could use his knowledge of future events to prevent certain tragedies, like the death of some of his comrades. Maybe he could change the way he approached his training, leading to even greater power earlier on.
Another possibility is Naruto traveling back to his own childhood days. He could mentor his younger self, teaching him advanced jutsu and wisdom he's gained over the years. This would make his younger self much stronger much earlier, and might also change how he interacts with Sasuke. For example, he could help his younger self better understand Sasuke's pain and prevent some of their earlier conflicts.
A cool plot would be Kakashi traveling back to a time during one of the great ninja wars, say the Third Great Ninja War. He could use his knowledge of future jutsu and strategies to turn the tides of battles that were previously lost. He might also be able to save comrades who died in the original timeline, and in the process, change the future of many ninja families.
A possible plot is that the Third Hokage travels back to when he first became Hokage. He realizes all the mistakes he made in his first term and gets a second chance to do things right. He could focus more on training the younger generation, like Naruto and Sasuke's predecessors, in a better way. He could also be more proactive in dealing with external threats and internal conflicts, which would have a huge impact on the future of Konoha.
A third plot might be that they travel to a time way before the founding of the ninja villages. Here, they could witness the origin of ninjutsu and the early clans. They may try to influence the development of the ninja world from its very roots, perhaps even trying to create a more unified and peaceful ninja society from the start without all the future conflicts that were based on old grudges and power struggles.
One idea could be Naruto facing a new and powerful enemy that challenges the very foundation of the Hidden Leaf while he's Hokage. He has to use his unique leadership style and ninja skills to protect the village. Another could be Naruto implementing new training programs for the younger ninjas, based on his own experiences growing up.
One idea could be a story where Naruto has to face a new, powerful and mysterious enemy that has the ability to manipulate time. This would put his skills as a Hokage to the ultimate test.
The idea of time travel in 'Naruto Hokage Time Travel Fanfiction' is appealing because it allows for a lot of 'what - if' scenarios. Fans can see how Naruto, as a Hokage, would change things if given a second chance. It's a chance to rewrite the story in a more ideal way.
One possible plot could be that fem Naruto travels back in time to her younger self. She uses her knowledge as a Hokage to prevent certain tragedies. For example, she could stop Sasuke from leaving the village in the first place. This would change the whole course of events in the Naruto world.
One popular plot idea could be a character with Mangekyou Sharingan traveling back in time to prevent a major tragedy in the Naruto universe. For example, stopping the Uchiha massacre. This would create a whole new set of events and relationships. Another idea might be a time - traveling ninja using the power of the Mangekyou Sharingan to gain knowledge from the past and use it to change the future of their clan. They could learn ancient jutsu or secrets that were lost over time.