There might be an old sage living in the mountains of one of the elemental nations. The sage has vast knowledge of ancient ninja arts and has been in isolation for years. Naruto's encounter with this sage could be a turning point in his journey, as the sage could offer him wisdom and perhaps even a new form of power or training method.
Sakura might be one of the characters. She has her own set of skills in the medical and combat fields. Meeting Harry could lead to exchanges of knowledge about different forms of healing and combat magic.
He could meet alternate versions of his friends. For instance, an alternate Sasuke who has never left the village and is a strong ally from the start. This Sasuke could be more open and friendly, and together they could face the challenges of the new universe.
Besides Naruto, Hinata could play a significant role. As Naruto's wife in the original series, she could be his support and also use her Byakugan abilities to help Naruto keep an eye on the different regions of the elemental nations. Shikamaru, with his intelligence, might also be a key character, helping Naruto with strategic planning and handling political situations.
One interesting plotline could be Naruto making unexpected alliances with different clans in the elemental nations. For example, he might team up with a water - based clan and learn their unique water - style jutsu techniques, which he can then combine with his own skills.
Perhaps Naruto would meet other jinchuriki in his travels around the world. They share a unique bond as they are all hosts of tailed beasts. Together, they could support each other, exchange experiences about living with the beasts inside them, and become great friends in the process.
Perhaps an old enemy that Naruto thought was defeated has returned, stronger than ever. This enemy could hold a grudge against Naruto and the elemental nations for past defeats and wants revenge.
He could meet Pain. Since Pain was from Amegakure, Naruto might encounter him or learn more about his past in the village. It would be an interesting encounter as they had a major battle before.
He could meet a wise old fox - like furry who imparts some important life lessons to him. This character might be like a mentor figure, guiding Naruto on his new furry - filled journey.
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.
Naruto may run into some friendly space explorers who are amazed by his ninja skills. They could help him navigate the strange new world of space and introduce him to advanced technologies that are different from what he's used to in the Hidden Leaf Village. There might also be some wise, old beings in space who can teach Naruto new ways to master his chakra.