Another plot twist could be related to Kakashi's own abilities. Since he has knowledge of the future, he might try to use some jutsu or skills that he hasn't learned yet in his original time. But this could come with a cost, like draining his chakra too much or attracting unwanted attention from powerful enemies. He could also accidentally teach his past self some skills that change the course of his own development.
A possible plot twist could be that when they travel back, they find out that the past is not as they remembered it. Maybe some events were actually caused by an unknown enemy manipulating things from the shadows all along.
One possible plot twist could be that Naruto, when he travels back to graduation, realizes he has some of his future skills and knowledge. He might use this to outperform everyone in the exams in unexpected ways, like using advanced jutsu that no one has seen before, which would shock his classmates and teachers.
If Kakashi time - travels to the Kannabi Bridge, his relationship with Obito would be very different. Instead of the tragic end they had in the original timeline, Kakashi might be able to save Obito. This would lead to a much closer bond between them, and they could become a powerful duo in the ninja world. They might also be able to change the future of the Uchiha clan together.
A great plot twist could be that Darth Vader travels back to the time when the Jedi Order was at its peak. His dark side presence is detected by the Jedi Council immediately. However, instead of being able to simply capture or kill him, they find that his knowledge of future events gives him an edge. He might use this to manipulate the Jedi, creating internal strife within the Order. This could also lead to some Jedi being tempted by the dark side because of the power that Vader represents. And all of this could ultimately reshape the future of the galaxy far more than anyone expected.
One possible plot twist could be that Luffy's time travel alters the fates of some of the characters who died at Marineford. For example, he might be able to save Ace. Another could be that his presence in the past changes the future relationships between the pirates and the Marines in unexpected ways. Maybe some pirates who were once enemies now become allies because of Luffy's interference.
One interesting plot twist could be that the Titanic travels to a future where sea levels have risen drastically. The ship, which once was a symbol of luxury travel, now becomes a symbol of a bygone era struggling against the new, harsh environment. The survivors have to adapt to this new world and use the ship's resources in ways they never imagined.
One possible plot twist could be that Kakashi, as a girl, has to deal with different social expectations in the ninja world. For example, she might face more restrictions in combat training because of her new gender. Another could be that she uses her new form to her advantage in undercover missions, fooling enemies who are less likely to suspect a female. Also, there could be a romantic plot twist where a character who previously saw Kakashi as a rival now has different feelings for her as a girl.
One possible plot twist could be that Naruto actually steals something from Kakashi that he thought was unimportant, but it turns out to be a key to a hidden jutsu or a secret mission. Another could be that Kakashi knew Naruto was going to pickpocket him all along and let it happen as part of a training exercise. Maybe Naruto pickpockets Kakashi, but then realizes he has to return the item quickly because it's something that Kakashi needs to save the village.
One possible plot twist could be that it's all a dream of Sakura's. Maybe she has a deep - seated longing for Kakashi, but she's been suppressing it. And the kiss in the fanfiction is her subconscious mind's way of expressing that hidden desire.
One possible plot twist could be that Sakura discovers Kakashi has a secret past she never knew about. Maybe he was involved in some kind of dangerous mission long ago that has consequences in the present. This could put a strain on their relationship as she tries to come to terms with this new information.