Draco Malfoy would be a likely character. Since they are in the same house now, they would have more opportunities to interact. Their relationship could start off as hostile as always, but then gradually change as Hermione shows different aspects of herself in Slytherin.
Another development could be her relationship with the other houses changing. The Gryffindors might initially be suspicious of her new Slytherin status. However, Hermione could use this as an opportunity to bridge the gap between the two houses. She could show that just because she's in Slytherin doesn't mean she's abandoned her Gryffindor courage and loyalty.
If Hermione was sorted into Slytherin, she'd bring a whole new dynamic to the house. Slytherin is known for its ambition and resourcefulness, and Hermione has those traits in spades. She might change the perception of what it means to be a Slytherin. Instead of just being about pure - blood supremacy and cunning for the sake of it, she could introduce a more ethical form of ambition. Her study habits would probably influence some of the other Slytherins to be more studious. And she'd also have to navigate the politics within Slytherin, which could be a real challenge as she's used to the more straightforward environment in Gryffindor.
Well, he might face a lot of challenges. In Slytherin, he'd be surrounded by students with different values compared to Gryffindor. He could have a tough time making true friends at first. But it might also give him a chance to change the perception of Slytherin from within. He could use his Gryffindor courage to influence the more cunning and ambitious Slytherins towards a more positive path.
One idea could be Hermione using her intelligence to change the Slytherin house's reputation from within. She could start study groups that include students from all houses, gradually breaking down the traditional rivalries. Another plot could involve her befriending some of the more misunderstood Slytherin students and together they work on a secret project that benefits the whole school.
One interesting plotline could be Hermione struggling to fit in Slytherin at first. She's used to the values of Gryffindor, so being in Slytherin where ambition and cunning are prized in a different way would be a big adjustment. For example, she might have to deal with the initial suspicion from her Slytherin housemates who are not used to having a 'Mudblood' among them. But as time goes on, she could use her intelligence to show them that she belongs there and maybe even change some of their views on blood purity.
Well, if Hermione were sorted into Slytherin, it would drastically change the story. For one, her relationship with Harry and Ron would be strained at first. They might be suspicious of her motives. In the original story, Gryffindor values bravery and Hermione often showed that. But in Slytherin, she'd have to navigate the house's more cunning and ambitious nature. This could lead to her using her intelligence in different ways, perhaps more self - serving initially. It would also change the dynamic in the Slytherin house. She could potentially influence some of the Slytherins to be more open - minded, or she might face a lot of opposition from the more traditional Slytherins who don't like outsiders. Overall, it would be a very different Hogwarts experience for her.
One common trope is the outsider - within - Slytherin. Hermione is smart and different from the typical Slytherin, so she has to find her place. Another is the redemption of Slytherin as a whole. With Hermione there, she might start to change the house's more negative aspects. There's also the friendship - turned - rivalry - turned - friendship again with characters like Draco. They start off on the wrong foot, become rivals, but then realize they can work together.
Well, usually it leads to a lot of interesting plot twists and character developments. Maybe Snape has a hidden agenda or Hermione discovers new sides of herself in Slytherin.
There's a fanfic titled 'Harry in Slytherin: Overcoming Abuse'. In it, Harry's sorting into Slytherin is a shock to many. But within Slytherin, he finds a sense of belonging. The house's values of ambition and self - preservation help him deal with his abuse. The story shows how he transforms his pain into strength with the support of his Slytherin peers. It's a story of redemption and growth.