Maybe a mysterious ninja from a hidden clan shows up. This ninja is intrigued by Naruto's situation of being left behind by Sakura and decides to help him. They could have some really cool powers like the ability to manipulate shadows in a different way than the Nara clan. Also, there could be a healer from a neighboring village who comes to Konoha. She helps Naruto deal with his emotional wounds from being left behind, and in the process, they become good friends.
A new character could be an old friend of Naruto's parents who shows up. They might have some information about his family and why he was left behind. Maybe there's a healer who tries to help Naruto deal with the emotional scars of being left behind. This healer could have their own backstory related to loss and abandonment as well.
One possible plot could be that Naruto feels abandoned by Sakura after she chooses Sasuke over him. Naruto then goes on a journey of self - discovery, training harder than ever to prove his worth not just to Sakura but to the whole village. He might face new enemies alone and form unexpected alliances, all while dealing with the emotional pain of being left behind.
There could be a hermit who takes Naruto in during his banishment. This hermit could teach him some ancient ninja techniques. Another new character might be a fellow outcast that Naruto meets, and they form a bond while living on the fringes of society.
There could be air - based ninja clans with their own unique abilities. For instance, a clan that can manipulate air pressure to create powerful blasts or shields. These new characters would bring fresh fighting styles to the Naruto world.
It's hard to say for sure. But perhaps there could be ninjas from a far - off land that we haven't known about before.
There could be a new character who is a mysterious wizard from another dimension. He comes to help Sakura in her trials, but his motives are not entirely clear at first. He has his own set of magical powers that are different from Sakura's, like being able to transform into different animals.
Maybe a group of rogue ninjas who initially see Naruto as a target but then end up joining forces with him. They have different skills and personalities that add to the story.
There could be their children's friends. Maybe a young ninja from a far - off village who comes to study in the Hidden Leaf. His unique abilities and different cultural background could bring new elements to the story.
A new Akatsuki member, a young and powerful ninja who has a personal vendetta against Naruto. Their clashes could add a lot of drama and action to the fanfic.
Kakashi could also play a role. He has always been a mentor to Naruto and his sense of duty and loyalty to his student might drive him to search for Naruto when he hears that he's been left for dead. He has the skills and knowledge to find and save Naruto in a difficult situation.