Maybe some local tribespeople who have unique abilities or knowledge. For example, they could teach Naruto some ancient techniques or survival skills that are not known in the Hidden Leaf Village. There might also be wandering samurai or other shinobi from different regions who pass by the outpost and interact with Naruto.
Naruto could meet some outcasts who have been living in the outskirts near the outpost. These people might have been shunned by society for various reasons. By interacting with them, Naruto would gain a new perspective on the world. He might also meet some mysterious hermits who possess great power and wisdom. These hermits could see the potential in Naruto and decide to mentor him in some way, helping him to grow even further during his time of banishment.
In this kind of fanfiction, Naruto might face a lot of challenges. He could be isolated from his friends and the village he loves. Maybe he has to deal with local problems at the outpost all by himself, like fending off wild beasts or bandits. Also, he might start to question his place in the world since he was banished.
He would surely meet Gaara. Gaara, having had his own experiences of being an outcast, would likely be one of the first to interact with Naruto. They could share their stories and become good friends.
He could meet Mei Terumi. She is a powerful and important figure in Kiri. Naruto might have some interesting interactions with her, either as an ally or having some initial misunderstandings with her. Another character could be Chojuro. He's a kind - hearted ninja, and he might be one of the first to welcome Naruto in Kiri.
He might meet other banished shinobi who have formed their own small community. They could teach him different techniques that are not known in Konoha.
There could be a group of kids on the beach who are inspired by Naruto. They might approach him and ask for autographs or to show them some ninja moves. Naruto would be happy to oblige and in the process, he could discover a new talent among the kids that could be important for the future of the ninja world.
If Naruto is banished to the My Hero Academia universe, Deku could be his ally. Deku, with his determination to be a hero, would understand Naruto's drive to be recognized. They could share their experiences of being underestimated at first. Also, in a crossover with the Inuyasha world, Kagome could be an ally. She has a kind heart and could help Naruto understand the new world he's in. Her spiritual powers might also interact in an interesting way with Naruto's chakra.
Sasuke could be an ally. Despite their past differences, Sasuke might see the injustice of Naruto's banishment and decide to join him. He could bring his powerful Sharingan skills to the new village. Also, some of Naruto's old friends like Shikamaru or Choji might secretly support him and provide resources or information. They could be like undercover allies still within the old village but helping Naruto's new village in various ways.
He could marry Hinata. Even though he's banished, Hinata might follow him because of her deep love for him. Their relationship could develop further outside the village, and they could get married and start a family.
It could be an original character created specifically for the fanfiction. Maybe a young, talented singer who was once beloved but then falls from grace when Naruto discovers their true nature.
He could meet an AU version of Hinata who is more assertive and outgoing. Maybe she's a powerful ninja in her own right and not as shy as in the original story.