Maybe an older Slytherin student who has been influenced by the dark arts and doesn't want Harry to disrupt the status quo in Slytherin. This student could be envious of Harry's status as the WBWL and his growing influence in the house, and thus tries to undermine him at every turn.
Well, the main plot could be about Harry being a different kind of hero in Slytherin. Maybe he uses his unique skills and the knowledge from being the Boy Who Lived (WBWL) to change the perception of Slytherin in the wizarding world. He could be on a conquest to make Slytherin a more inclusive and positive house, defying the traditional dark and cunning stereotypes associated with it.
One common theme is identity. Since Harry is in Slytherin instead of Gryffindor, he has to re - evaluate who he is. He's no longer the typical Gryffindor hero, and he has to figure out how to be a hero in his own way while being part of a house known for its cunning.
Yes, Harry Potter Is Going to Be the Dark Lord was about how Harry Potter was sent to Slytherin during the Sorting. I hope you like this fairy's recommendation. Muah ~😗
One popular 'wbwl slytherin harry fanfic' is 'The Slytherin's Heir'. In this fic, Harry is sorted into Slytherin and it explores his journey in a very different light compared to the original story. He forms unique relationships with his housemates and faces different challenges.
One idea could be exploring the sorting hat's origin more in - depth. Maybe it was created by a powerful wizard long ago with a specific purpose, like maintaining the balance between the houses. Another could be a story where the sorting hat has a malfunction and starts sorting students into completely wrong houses, creating chaos at Hogwarts.
Perhaps the girl has a special connection with the Sorting Hat. It could be that the Hat reveals a hidden prophecy about her when it is placed on her head. This prophecy then sets her on a path to save Hogwarts from a new and unknown threat. She might have to team up with students from all the houses to fulfill the prophecy, and in the process, learn about the true meaning of unity among the houses.
There could be other original characters in the fanfic as well. Maybe there's a mysterious teacher who has a deep understanding of the Sorting Hat's magic. This teacher could help the girl unlock the secrets of the Sorting Hat and her own potential. And then there could be a rival student, perhaps from a different house, who challenges the girl at every step. Their interactions could drive the story forward and add conflict and drama to the plot.
Perhaps an ancient evil force that has been trapped in the Sorting Hat for centuries and is trying to use Hermione as a means to break free. The force could start influencing Hermione's thoughts and actions in a negative way, and she has to fight against it with the help of her friends and the positive magic of Hogwarts.
A young wizard or witch who has a natural gift for seeing auras. This character could be used to add a new dimension to the sorting process. They might be able to see the true nature of a student better than the sorting hat and could either help the sorting hat or cause some confusion when their observations don't match what the hat decides.