One possible scenario could be in a fanfic where Sakura accidentally uses her strength during a training session with Naruto and physically hurts him. Maybe she misjudges her punch or kick.
It could be due to differences in their ideologies. Naruto has his own set of beliefs about friendship, power, and redemption. These might clash with Raven's more complex and often darker view of the world. This clash could lead to Raven taking actions against Naruto that result in her hurting him.
In some 'naruto gets hurt fanfic', it could be due to a trap. He might be exploring an unknown area, perhaps an ancient ruin or a hidden lair. There could be traps set by previous occupants or enemies. Naruto, being curious and brave, might trigger one of these traps and get hurt. For instance, a poison - dart trap or a collapsing floor.
His friends would most likely rally around him. Kiba might use his dog Akamaru to scout the area and make sure there are no other immediate threats. Hinata would be really worried and would try to use her Byakugan to see if there are any hidden enemies or if Naruto has any internal injuries. Choji would offer some of his food to Naruto to give him strength, as his clan's food can have special effects on a ninja's body.
Maybe the enemy would see Naruto's injury as an opportunity to finish him off. But Naruto has a habit of surprising his foes. Even in his hurt state, he could pull off some unexpected jutsu. His friends could also use this situation to set up a trap for the enemy. For example, they could make it seem like Naruto is more injured than he actually is, luring the enemy into a false sense of security before attacking.
In other fanfics, Naruto might try to understand Sakura's perspective. He's a very forgiving person, so he could give her the benefit of the doubt and try to figure out what made her act in a way that hurt him. He might think that she had her reasons and try to work through it with her.
Kakashi Sensei could also be involved. He is Naruto's teacher and mentor. If Naruto gets hurt during a mission that Kakashi is leading, Kakashi would surely be there. He might feel responsible for Naruto's injury and would do everything he can to protect him further and get him to safety. And then there's Pain. In some fanfics, Pain could be the one who attacks Naruto and causes him to get hurt, especially if the fanfic is centered around the events related to Pain's invasion.
There are several typical situations in fanfic where Naruto is hurt by villagers. Sometimes, the villagers' children are influenced by their parents' negative views of Naruto and bully him at school or in the streets. This can range from simple name - calling to more serious physical abuse. In other cases, the adults in the village might try to undermine Naruto's achievements. For instance, when he passes a difficult ninja exam or accomplishes a mission, instead of getting praise, the villagers find ways to downplay his success, saying it was just luck or that he had some unfair advantage. This continuous undermining of his worth by the villagers is a common source of his pain in fanfics.
It could be that Anko is under some sort of mind - control in the fanfiction. And because of that, she attacks Naruto without really meaning to. Maybe she has been influenced by an enemy's genjutsu. So, she uses her powerful attacks on Naruto, and he gets hurt as a result.
Another possibility is that Naruto was trying to protect someone else from Sasuke. Suppose Sasuke was on a path that would endanger another important character in the story, like Sakura. Naruto, in his eagerness to safeguard Sakura, might have accidentally hurt Sasuke while trying to stop him from taking any harmful actions.