In some fanfictions, Sasuke might get hurt by a curse that was placed on him long ago. As he suffers, he has visions of his past, his family, and his mistakes. His struggle with the physical pain and the emotional turmoil of his past makes for a very engaging and complex storyline.
A common reason is battles. Sasuke is often involved in intense combat situations in fanfiction, whether it's against old foes with new powers or entirely new enemies. His determination to prove himself or protect something often leads him to take risks that result in getting hurt.
One possible storyline could be that Shikadai is on a mission and gets caught in an unexpected ambush by a group of powerful enemies. He might be outnumbered and sustain injuries while trying to fight them off and protect his comrades. Another could be that he's involved in a training accident that goes horribly wrong, like a jutsu backfiring on him and causing him physical harm.
In some George Weasley hurt fanfictions, an emotional moment could be when his friends first see him injured. Their shock and worry can be really touching. For example, if he gets hurt during a Quidditch match, his teammates' reactions of gathering around him, their faces filled with concern, can be quite moving.
One emotional moment could be when his friends find him hurt. Their expressions of shock and worry really tug at the heartstrings. For example, Jay might be speechless for a moment, his eyes wide with fear. Another moment could be when Zane himself is in pain but trying to be strong for his friends, like when he forces a smile through his injuries to reassure them.
Maybe Spike tries to prove himself by joining in on a dangerous adventure with the Mane 6. They are exploring an old, abandoned castle filled with traps. Spike, being smaller and not as experienced as the others, steps on a pressure - sensitive tile that releases a volley of arrows. He gets hurt as some of the arrows graze his body, and then the group has to figure out how to treat his wounds while still making their way through the dangerous castle.
One possible storyline could be that Brennan is injured during an excavation. Maybe a cave - in occurs and she gets trapped under some rubble. Her team then has to race against time to save her while she struggles with her injuries. Another could be that she is attacked while working late at the Jeffersonian. This would not only lead to her physical hurt but also psychological trauma as she tries to figure out who did it and why.
In some fanfictions, JJ could get hurt during a hostage situation. For example, she might try to negotiate with the hostage - taker, but things go wrong and she gets shot. Her injury then becomes a catalyst for the team to work even harder to resolve the situation. Another idea is that she is targeted by a cult because of her work with the BAU. They manage to capture her and inflict harm on her, and the story could revolve around the team's efforts to rescue her and take down the cult. Also, she could be injured in a car accident while chasing a suspect, and the team has to deal with their fear of losing her while also trying to solve the case that led to the accident.
In a more complex storyline, Evan could get hurt as a result of some sort of conspiracy against the medical practice. Maybe someone is trying to sabotage the hospital and they target Evan as he is often involved in the administrative side. They set up a situation where he is exposed to a harmful substance or gets physically attacked, which then leads to a long journey of recovery and uncovering the truth behind the attack.
In such fanfictions, characters like Bruce Wayne might feel guilt. He could blame himself for not protecting Jason better. Dick Grayson may be angry at the situation and determined to find out who's responsible. Barbara Gordon might show concern and try to use her resources to help Jason's recovery.
One possible storyline could be that they are on a case and get caught in a trap set by the unsub. For example, they might be lured into an abandoned building where the unsub has rigged it to collapse. JJ could get trapped under some rubble while trying to protect Penelope. Another could be that they are poisoned during an investigation. Maybe they accept food or drinks from someone connected to the case who has ulterior motives. Penelope might be the first to show symptoms, and JJ is desperately trying to find a cure while also dealing with her own growing illness from the poison.