The other main characters could include the Hokage of that time, like Hiruzen Sarutobi. Naruto might interact with him to try and influence the decisions of the village. Also, members of the Uchiha clan such as Itachi would play significant roles as Naruto could try to change their fates as well.
Obviously, Naruto and Kurama are going to be main characters. Since it's about Kurama going back in time, he'll be central to the story. Naruto will also be important as Kurama's jinchuriki and the one whose life Kurama is likely to impact. Minato might also be a significant character as he was Naruto's father and had a major role in the original story. And there could be appearances from other key characters like Sasuke, as Naruto's relationship with him was a big part of the original Naruto series.
Obviously Naruto would be one of the key characters. Since it's about his generation going back in time, he would be central to any attempts at changing the past. His knowledge and his will to protect his village would drive many of the actions.
Gohan will most likely encounter other Z - fighters like Krillin and Tien. They were all part of the group back then. Also, there's a good chance he'll meet Master Roshi. Roshi was a key figure in Goku's training, so his interaction with Gohan could be really interesting. He might also come across Bulma, who was always involved in the Dragon Ball story, either by accident or because he needs her help with some time - related technology or something.
Naruto would be a very likely character to interact with Hinata. Since they have a strong connection in the original story, in a time - travel scenario, their relationship could develop in new and interesting ways. Maybe Hinata could be more open with her feelings earlier in time.
Sasuke is also very popular. As Naruto's friend and rival, many fanfictions explore how their relationship would be different if Naruto had a second chance. For example, Sasuke might be more open to Naruto's friendship earlier due to Naruto's new approach influenced by his future knowledge.
In 'Harry goes to Marauders time' fanfiction, Harry is the central figure. Alongside him, the Marauders are essential. James, the confident and sometimes arrogant young wizard, will be there. Sirius, the rebellious and loyal friend. Remus, the kind - hearted werewolf. And Peter, who might be on a different path in this alternate timeline. Lily, with her kind nature and powerful magic, will also be a prominent character. There could also be other Hogwarts professors from that time, like Dumbledore, who could play a role in Harry's journey in the past.
Obviously Naruto would be one of the main characters. And from the Nova Corps, likely some of their leaders or important members like Rhomann Dey.
Obviously Naruto himself. Since he is the one going to the past, he would be the central character. His younger self would also be important as he would interact with his future self.
In 'Desmond goes back in time fanfiction', Desmond is surely a main character. He could meet his own family members from the past, and they could be important characters too. For instance, his great - grandfather might be a key character. There could also be a love interest for Desmond in the past, a local girl perhaps, who adds an element of romance to the story and also influences his actions and decisions while he's in the past.
There could also be characters from the past that become central to the story. For example, if they go back to the time of the First Hokage, Hashirama Senju could be a major character. Team 7 might interact with him, learn from him, or even have to work with or against him depending on the plot of the fanfiction.