Perhaps Sam gets hurt while trying to protect a civilian. He jumps in front of a werewolf's attack meant for someone else. This would show his selfless nature. The local hunters in the area might not trust Sam and Dean at first, but seeing Sam's sacrifice could change their minds, adding an interesting dynamic to the story.
One type of fanfiction could be where Sam gets hurt during a hunt. Maybe he's attacked by a powerful supernatural creature and has to deal with a serious injury while Dean tries to find a way to save him. It could explore his physical and mental pain, and how he copes with the situation.
One idea could be that Sam is kidnapped by a group of rogue hunters who think he's gone too far in his use of demon powers. They lock him in an abandoned bunker and try to 'exorcise' the 'demon' out of him, not realizing he's in control. His brother Dean has to race against time to find him, following a series of cryptic clues left by the kidnappers.
Another aspect is how it affects the relationships in the story. If Sam is hurt, it can put a strain on his relationship with Dean. Dean might feel guilty for not being able to protect him. Or it could strengthen their bond as Dean devotes all his time to taking care of Sam and making sure he gets better.
One common plotline could be Sam getting physically hurt during a hunt and his brother Dean having to take care of him. For example, in some fanfictions, Sam might be injured by a supernatural creature like a werewolf. Another plotline could involve Sam being hurt emotionally, perhaps due to a betrayal within the hunting community or a difficult decision he has to make. Sometimes, fanfiction writers explore Sam getting hurt as a result of a spell gone wrong, which then leads to a series of events where the other characters have to find a way to reverse the effects.
Sometimes it's due to Dean's overprotectiveness. He might think he's doing what's best for Sam but in the process, his actions end up causing harm. For instance, he could keep Sam from a mission that Sam believes is important, and in the struggle, Sam gets hurt.
Well, it depends on the type of fanfiction. In darker fanfictions, Sam getting shot could be the start of a downward spiral for the Winchester brothers. Dean could become overly consumed with revenge if it was a hunter or a monster that shot Sam. On the other hand, in more positive fanfictions, Sam getting shot could lead to a moment of self - discovery. He might realize how much he has to live for and how many people rely on him. Maybe it makes him reevaluate his relationships, like his bond with Dean or his friends in the hunting community.
Well, Dean would probably go into full - on search - and - rescue mode. He'd start by reaching out to all their contacts in the hunter community. Maybe he'd call Bobby in spirit form if he could, asking for any leads or advice. He'd also check Sam's last known locations and look for any signs of a struggle.
Perhaps Sam gets hurt while trying to protect a civilian in Flashpoint. The civilian feels guilty and tries to help in his recovery. This could lead to an interesting bond between them. Meanwhile, Sam's team is investigating who was behind the attack on the civilian that led to Sam's injury, and they uncover a conspiracy within the Flashpoint society.