Another interesting plot could be Sam forming a connection with other werewolves. Maybe he discovers a pack that has different values than the ones he's used to fighting, and he has to decide whether to side with them or stay with his hunter ways. This creates a moral dilemma for him. There could also be a plot where Sam's werewolf nature attracts a powerful and dangerous enemy that specifically targets him because of his unique condition. It forces him and Dean to find new ways to protect themselves and defeat the enemy.
A plotline could be that on Halloween, Sam and Dean discover a town where every year, people disappear mysteriously. They suspect it has something to do with an ancient Halloween ritual gone wrong. As they dig deeper, they find that a group of cultists are trying to summon a powerful entity. Sam uses his research skills to find a way to stop the summoning, while Dean prepares for a fight.
One possible plotline could be Sam being captured by a villain and gagged to prevent him from using spells or calling for help. Another could involve a prank gone wrong within the Supernatural universe where Sam ends up gagged in a humorous yet tense situation. Maybe there's a plot where an otherworldly entity has the power to silence Sam by gagging him to stop his investigations.
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.
One possible plotline could be a werewolf's struggle to control their 'in heat' instincts while in a human - populated area. They might have to deal with the challenges of hiding their true nature from friends and family.
In Supernatural fanfiction, a frequent plotline involving Sam and Bela Talbot is that of a reluctant partnership. Bela might drag Sam into one of her heists that ends up being more than she bargained for, and they have to face some terrifying supernatural entity together. Or perhaps Bela double - crosses Sam at first, but then realizes she needs his help to survive a situation. There are also plotlines where Sam tries to reform Bela, seeing some good in her that she doesn't even see in herself.
One common plot is exploring what could have happened if Madison had survived. Maybe she and Sam could have had a life together away from the hunting world, like living in a small town and trying to be normal.
There might be a fanfiction where Sam and Bella accidentally travel to an alternate dimension. In this dimension, they have to rely on each other completely to find a way back home while also facing strange and new supernatural threats.
One interesting plotline could be them collaborating on a big musical number for a school competition. They might start off with different ideas but then combine their talents to create something amazing.
One possible plotline could be Hermione's attempts to find a cure for the werewolf curse for her werewolf friend. She might use her vast knowledge of magic to research ancient spells and potions.
Perhaps there's a plotline where Naruto, as an alpha werewolf, has to form a pack within the world of ninjas. He could recruit other characters who are also werewolves or those who accept his dual nature, and they work together to protect the village from new threats that are specifically targeting werewolves.