He might meet some old enemies who have changed sides. They could offer their help, seeing Naruto's selfless act.
Naruto could meet some mysterious characters that are only known in the fanfiction world. These characters might have unique abilities that could either help or hinder his mission. He may also come across some of his former sensei or mentors in a spiritual form, guiding him through the difficult times of the mission.
There's a chance he could meet an older and wiser Kakashi. Kakashi might have new insights and stories to share with Naruto from all the years that have passed. And also, he could run into future shinobi who look up to him as a legend from the past.
Naruto might meet Itachi in heaven. Itachi could finally reveal all the secrets and the true intentions behind his actions to Naruto. And they could become true friends without any misunderstandings. Additionally, Naruto could also meet Neji, and they would talk about how the ninja world has changed since Neji's sacrifice.
Naruto could meet some young Uzumaki ninja - in - training. They would be excited to meet someone as famous as Naruto and might learn a lot from him. Also, there could be some reclusive Uzumaki who have been hiding special abilities that Naruto discovers during his stay.
Perhaps Naruto will meet some young ninja trainees in Uzu no Kuni. They might be inspired by Naruto and his stories from Konoha. They could also teach Naruto some unique ninja techniques that are specific to Uzu no Kuni. For example, they might have a special way of using water - based jutsu that Naruto has never seen before. And through interacting with these young trainees, Naruto could also gain a new perspective on ninja life outside of Konoha.
He could meet an alternate version of himself. This Naruto might have made different choices in life, like choosing not to pursue being a Hokage. It would be interesting to see how they interact.
There's a good chance he would meet Itachi. Itachi had a complex relationship with Naruto and played an important role in the overall story. In heaven, they could clear up any misunderstandings and Itachi could explain his actions more fully to Naruto, and Naruto could perhaps offer his forgiveness and understanding.
In the 'Naruto goes to the North' fanfic, he may come across a group of nomadic ninjas. These ninjas have a different way of life compared to the ones in Konoha. They might be more in tune with nature and have unique abilities related to the natural elements of the North. Naruto could learn a great deal from them and they could also be potential allies in his adventures in the North.
Well, in such a fanfiction, Naruto might face extremely difficult opponents. He could be outnumbered and in a situation where victory seems impossible. Maybe he would use some unexpected jutsu or strategy to try and turn the tables.
He might meet some of the past hosts of the Kyuubi. These past hosts could share their experiences with Naruto, giving him valuable insights on how to handle the power of the Kyuubi. It could be like a gathering of all those who have carried this great burden and power before him.
There's a chance Naruto meets some of Tenten's regular customers. These could be other ninja from the village who are also looking for supplies. Naruto might interact with them, sharing stories about his recent adventures while they browse through the items in the shop.