One common theme is redemption. For example, Sasuke might go back in time and try to fix the wrongs he did in the original timeline. Another theme is love. Hinata might use the time travel to get closer to Naruto earlier or in a different way.
A common theme is dealing with the consequences of time travel. They can't just change things willy - nilly without consequences. In many fanfictions, they have to carefully consider their actions because any small change could have a huge impact on the future. And there's also the theme of nostalgia. Returning to the past brings back memories and emotions, and they often have to deal with how they feel about their past selves and the events that happened back then.
One common theme is redemption. For example, Hinata might travel back in time to try and save Sasuke from his darker path. Another theme is the exploration of alternate relationships. Since Hinata and Sasuke don't have a major relationship in the original Naruto series, in these fanfictions, their relationship gets explored in new and interesting ways.
Love and relationships are also very common themes. The unrequited love that Sakura had for Sasuke for a long time, and Hinata's love for Naruto are often explored in different ways. Fanfics may show how these relationships develop and change as the characters mature.
One common theme is love and loyalty. In fanfictions about Sasuke and Sakura, Sakura's loyalty to Sasuke despite his past actions is often explored. Similarly, for Naruto and Hinata, Hinata's long - standing love for Naruto is a big part. Another theme is family. Stories might show how Sasuke and Sakura or Naruto and Hinata build their families.
One common theme is the chance to rewrite history. Since it's time travel, Sakura or Sasuke often get the opportunity to change events that they regret in their original timeline. For example, Sakura might try to prevent Sasuke from leaving the village in the past.
One common theme is redemption. For example, Sasuke might get a chance to correct his past mistakes by going back in time. Another theme is prevention. They could prevent the death of important characters like Jiraiya or Neji. And of course, there's the theme of self - discovery. As they interact with their younger selves, they learn more about their own growth and development.
In a time - travel fanfiction, they could go back to their own childhoods. Naruto could give his younger self some advice on how to deal with loneliness. Sasuke might be able to prevent his family's massacre. Sakura could start training earlier and become even stronger, and Hinata could overcome her shyness more quickly and become a more confident ninja.
One common theme is redemption. Hinata might go back in time to right the wrongs she or others have committed in the original timeline. Another theme is love. Since Hinata has feelings for Naruto, time travel can be a way to explore a different kind of relationship development, like falling in love all over again in a different context.
If they time - travel, Naruto and Sasuke's relationship could become even stronger. They might have a chance to bond over their shared knowledge of the future. Sakura could become closer to both of them as they work together in the past. Hinata, who has always admired Naruto, might find new ways to support him and also become better friends with Sakura.
Love triangles are also quite common. Since Naruto has a connection with both Sakura and Hinata, many fanfictions revolve around this love triangle. They explore different possible outcomes of who Naruto might end up with and how it affects the other relationships. Also, the theme of sacrifice often comes up. Each character is willing to sacrifice for their friends and for the village, and fanfictions play with these selfless acts in different storylines.