Maybe the time travel is caused by a mysterious time - space ninjutsu. In the past, Naruto and Sasuke find themselves in a world where their actions can have a huge impact on the future. The kiss could be a spontaneous reaction to the realization that they are the only ones who truly understand each other across time. As the story progresses, they might try to prevent certain tragedies from happening in the past, all while dealing with their new - found and complicated relationship.
In this type of fanfiction, the time travel might be a result of a forbidden scroll or an experiment by a rogue ninja. When Naruto and Sasuke go back in time, their relationship is different from what it was in their original time. The kiss could be a turning point where they start to understand their feelings for each other on a deeper level, perhaps realizing that their bond is stronger than just friendship or rivalry.
In such a fanfiction, they might try to prevent some of the tragedies that occurred in their own time. For example, Naruto could stop the Uchiha massacre, saving Sasuke's family and potentially changing Sasuke's entire path. Sasuke, on the other hand, might use his knowledge to help the ninja world avoid future wars. They could also meet their younger selves and impart wisdom or skills that they learned in their original timeline.
A popular one is 'Sasuke's Time - Twisted Journey'. In this fanfic, Sasuke goes back in time and has to deal with his past self. It's full of action and emotional moments. The author does a great job of exploring Sasuke's character in a new light, as he grapples with his past mistakes and tries to make amends.
One great Sasuke, Naruto, and Sakura time travel fanfiction is 'Time - Twisted Bonds'. In this story, they are sent back to their childhood days with their present - day knowledge. It's really interesting to see how they interact with their younger selves and try to change things for the better. Another good one is 'Journey Through Time' where they travel to different points in the Naruto timeline and face challenges that were not part of the original story.
Well, while I haven't come across such a fanfiction myself, it's not out of the realm of possibility. Fanfiction often takes existing characters and relationships and twists them in unexpected ways. Given the popularity of Naruto, Sasuke, and Sakura, some fans might be interested in exploring this rather unconventional scenario in their creative writing. However, it might also be a subject that some fans would find too far - fetched or against the spirit of the original story.
I think Kakashi could be really popular. Since he has a connection to both Sasuke and Naruto, his role in a time - travel story could be very interesting. He might be able to help them adjust to the past or use their knowledge to his advantage. Another popular character could be Itachi. His actions in the past are so crucial to the story, and in a time - travel scenario, he could interact with Sasuke in a whole new way.
One possible plot twist could be that Sasuke, upon traveling to the past, accidentally changes a small event that has huge ramifications in the future. For example, he might prevent a key encounter that led to a character's development, and as a result, the entire power balance in the ninja world is altered. Another twist could be that Sasuke's presence in the past is somehow detected by an ancient and powerful force, which then tries to either use him or destroy him. Or perhaps, Sasuke discovers that his own past self is not as he remembered, and there are hidden motives or secrets that he was unaware of before.
There's also 'A Time - Traveling Trio'. This fanfiction focuses on how Naruto, Sasuke and Sakura's relationships change during their time - traveling adventure. They go back to key moments in their past and their interactions with each other and other characters are really well - written. It shows a different side of their friendship and rivalry as they work together to get back to their own time.
It needs to explore new and interesting scenarios. Maybe Sasuke travels back and tries to prevent certain tragedies from happening in his clan. The fanfic should also delve into the emotional aspects. How do the characters feel about being in a different time? Are they homesick? Do they regret their actions in the future? All these elements combined can make a great fanfiction.