Jiraiya. Naruto could have a different kind of apprenticeship with Jiraiya. He could share some of his future experiences with Jiraiya, which might change how Jiraiya trains him and also how Jiraiya approaches his own missions and prophecies.
One interesting plot could be Naruto using his future knowledge to prevent the Uchiha massacre. He might try to change Itachi's situation and find a way to resolve the conflict between the Uchiha clan and the village without all that bloodshed.
Naruto's character might develop a greater sense of responsibility as he realizes the impact of his actions in the past on the future. He may become more patient, knowing that he has to tread carefully to avoid major disruptions.
Naruto has been through a lot in his own time, so he may use that experience to adapt to the past. He might start by making friends with the younger versions of people he knows. He'll also have to be careful not to reveal too much about the future to avoid disrupting the timeline. He could use his ninja skills to earn respect and find his place in the past world.
One interesting plot point could be Naruto using his future knowledge to prevent certain tragedies in the past. For example, he might stop the death of a beloved character. Another could be his interactions with his younger self and how he imparts wisdom without revealing too much.
He'd probably be super surprised. I mean, seeing yourself as the opposite sex is not something that happens every day. He might blurt out something like 'Who are you? You look like me!' and then start to realize the situation. He could be a bit embarrassed too, especially if female Naruto had some different mannerisms or ways of dressing.
Well, one possibility is that Naruto might be really confused at first. He'd see this different version of himself as a female and might not immediately understand the situation. He could try to figure out how this time - travel happened and what it means for his world. Maybe he'd start to learn about the differences in how female Naruto is treated in this new world compared to his own experience as a male.
There are fanfictions where Naruto travels to a world full of magic, not just chakra. He has to adapt to using magic instead of his regular ninja skills. It's exciting to see how he copes with this new power source and the different creatures he meets. Some stories also have Naruto traveling to a post - apocalyptic version of the Naruto world. He then has to use his skills to help rebuild society and face new threats that emerged after the apocalypse.
He could also develop a deeper understanding of the history and roots of the Hidden Leaf. By being in the past, he gets to experience the events that shaped the village first - hand. This makes him more empathetic towards the founders and previous generations, and he might bring back a new sense of pride and respect for the village's heritage when he returns to his own time. Well, in some fanfictions, he might also struggle with the idea of changing the past too much. He has to balance his desire to make things better with the potential consequences of altering history, which adds a layer of moral complexity to his character development.