One possible plotline could be Sarutobi mentoring Naruto more closely. Since he's alive, he could pass on even more of his wisdom and jutsu knowledge to Naruto. For example, he might teach Naruto some of the more secretive fire - style jutsu that only he knows.
Perhaps Sarutobi plays a key role in uncovering some long - hidden secrets about Naruto's parents. Since he has a long history in the village, he might know some details that others don't. This could lead to Naruto learning more about his family heritage and unlocking new powers or abilities related to it.
One possible plotline could be Kushina getting to train Naruto personally. Since she was a powerful kunoichi, she could pass on her unique skills and knowledge. This would make Naruto even more formidable at an earlier stage. Another plotline might involve Kushina's influence on Naruto's relationships. For example, she could have a big impact on how Naruto interacts with Sasuke, perhaps helping to prevent some of the rifts that occurred between them in the original story.
A possible plotline could also be Naruto's struggle with loneliness and how he overcomes it. He might start writing letters to his friends (even if he doesn't send them) as a way to express his feelings, and through this, he gains a better understanding of himself.
Obviously Naruto would be one of the main characters interacting with him. Naruto would look up to Sarutobi as a mentor and a source of knowledge. Their interactions could range from training sessions to deep conversations about the future of the village.
One idea could be exploring the early days of the Sarutobi clan. Maybe show how they developed their unique jutsu. Another could be a story centered around a young Sarutobi clan member who has a rare ability and must prove themselves in the Hidden Leaf Village.
One interesting storyline could be Naruto learning some ancient and forgotten jutsus from Sarutobi Sensei. This could involve Sarutobi Sensei passing on his vast knowledge of unique techniques that were lost over time. Another could be a time - travel story where Naruto goes back in time and meets a young Sarutobi Sensei, and they team up to face a common enemy. It could also be a story where Sarutobi Sensei trains Naruto in the art of leadership, much like he did for the previous generations in Konoha.
One idea could be a fanfic where Sarutobi has to face a new and powerful enemy that threatens the Hidden Leaf Village in a way no one has seen before. This would test his leadership and combat skills.
One interesting Naruto Mirai Sarutobi fanfiction could be about his training journey. Maybe he discovers a new jutsu passed down secretly in the Sarutobi clan and has to master it while facing various challenges from other ninja clans. Another could be a story where he travels back in time and meets his ancestors, learning valuable lessons from them.
A great plotline would be if Jessica came back as a sort of supernatural being herself. Maybe she was brought back by a powerful witch, but not fully human. This would create a whole new dynamic as Sam would have to deal with her new state. She could be on a quest to find out who brought her back and why, and in the process, she and Sam could rekindle their relationship in a very different way compared to before.
One possible plotline could be Harry trying to hide his wizarding past from his muggle friends and coworkers. For example, he might accidentally use magic in a moment of panic and then have to cover it up.
One interesting plotline could be Harry learning the pure - blood traditions from the Malfoys in a different way than he expected. He might gain a new perspective on the wizarding world's social hierarchy.