One interesting plotline could be Naruto using his knowledge of the future to prevent certain tragedies that occurred during the war. For example, he might be able to save some of the fallen comrades. Another could be his attempts to change the political situation in the ninja world for the better, leveraging his experiences.
In some 'naruto time travels after the war fanfiction', a really cool plotline is Naruto trying to unite the ninja clans much earlier. He saw how divided they were during the war and realizes that if they were united earlier, a lot of the destruction could have been avoided. So, he goes back and uses his charisma and experiences to bring the clans together, changing the course of the ninja world's history in a very positive way.
In some fanfictions, Naruto might go back in time and try to save his parents. He could alter the events that led to their deaths. This would not only change his own life but also have a huge impact on the entire ninja world as his parents were very powerful ninja.
One possible plotline could be Naruto having to adjust to his new relationships within the harem. For example, dealing with the different personalities and needs of each girl. Maybe one girl is from a different village and there are cultural clashes that Naruto has to mediate. Another could be about how Naruto uses his newfound family - his harem - to help him rebuild the village in a more harmonious way.
One interesting plotline could be Naruto encountering different versions of his friends in various universes. For example, he might meet a Sasuke who is a powerful mage instead of a ninja. Another could be Naruto facing new and unique villains that only exist in certain multiverse realms. He may also have to adapt to different ninja cultures and power systems in different universes, which would be really exciting to explore.
One interesting plotline could be about the rebuilding of the Hidden Villages. Naruto could be deeply involved in diplomatic efforts to strengthen relationships between the villages, ensuring long - term peace. Another could be the exploration of the new generation of ninjas, their training, and how they are influenced by the war - heroes like Naruto.
One interesting plotline could be Naruto arriving in an alternate universe where the Akatsuki are the heroes. He has to figure out how to navigate this new world where his former enemies are now revered.
One interesting plotline could be Naruto making unexpected alliances with different clans in the elemental nations. For example, he might team up with a water - based clan and learn their unique water - style jutsu techniques, which he can then combine with his own skills.
One possible plotline could be Naruto arriving in a universe where chakra doesn't exist, and he has to learn new forms of power. Another could be that he meets alternate versions of his friends with different personalities. For example, Sasuke could be a pacifist in that universe.
One interesting plotline could be Snape going back in time and trying to prevent the death of Lily Potter. He might use his knowledge of the future to change certain events that led to her demise. Another could be him attempting to correct his own past mistakes, like his relationship with James Potter. Maybe he goes back and tries to befriend James earlier to avoid all the enmity that grew between them over the years.
One interesting plotline could be Harry going back in time to prevent certain deaths, like Sirius Black's. He might use his knowledge of future events to change the course of history and save his loved ones.
One interesting plotline could be Ron and Hermione's adjustment to a normal life after the chaos of war. They might struggle with things like PTSD and learning to live without the constant threat. For example, Ron could have nightmares about the battles and Hermione would be there to comfort him, strengthening their bond.