The 'redemption' trope is quite common. A Slytherin character who has been involved in some not - so - nice behavior in the past gets a chance at redemption through their friendship with Hermione. She helps them see a different way of life and values. Also, the 'fish out of water' trope can be seen when Hermione enters the Slytherin common room or their social circles. Her different values and ways of doing things create interesting situations and a platform for friendship to grow.
The 'hidden friendship' trope is also common. They keep their friendship a secret from the rest of the school because of the potential backlash. Draco might be worried about his Slytherin friends' reactions, and Hermione about her Gryffindor pals. So, they meet in secret places like the Room of Requirement to hang out.
A really interesting plot could be Hermione joining a Slytherin - led secret study group. In this group, Slytherins are researching some ancient and forbidden magic, not for dark purposes but out of pure academic curiosity. Hermione gets invited because of her reputation for knowledge. At first, there's a lot of tension as the Slytherins are not used to having a Gryffindor among them, but Hermione's eagerness to learn and contribute breaks the ice, and they become friends as they uncover the secrets of the magic together.
A great fanfiction could involve Hermione befriending a Slytherin during a wizarding war - related event. For example, they might be on opposite sides initially, but when they realize the true nature of the conflict and that they both want peace, they become friends. Their friendship then serves as an example to others that the house divide doesn't have to be so rigid.
In some fanfictions, Hermione might befriend a Slytherin who is an outcast in their own house. Maybe this Slytherin doesn't believe in the pure - blood supremacy ideals that some of their housemates do. Hermione, seeing their different perspective, decides to reach out. Their friendship then causes a stir among both Gryffindors and Slytherins, but they don't let it stop them from growing closer.
The allure also lies in the exploration of Hogwarts house politics. Fanfictions in this genre often break the traditional boundaries between houses. They show that students from Gryffindor and Slytherin can work together, fall in love, or form strong friendships. It gives readers a new perspective on the wizarding world that J.K. Rowling created, which is very appealing.
The 'time - travel' trope is also common. As I mentioned before, it can be really interesting to see them go back in time and interact with the younger versions of themselves or other characters. It often leads to a lot of plot twists and revelations.
One common trope is the 'time - travel' one. As in, Hermione travels back in time and gets involved with Fabian and Gideon. It allows for a lot of interesting interactions and plot developments. Another is the 'hidden connection' trope, like Hermione having some sort of ancestral or magical link to the Prewett family.
One way Hermione could make friends with Slytherins in fanfiction is through shared academic interests. For example, in the wizarding world, potions is a complex subject. Hermione is known for her academic prowess, and there are surely Slytherins who also take pride in their potion - making skills. If Hermione were to collaborate on a difficult potions project, it could be a starting point for friendship. She could also show respect for their house traits like ambition and cunning. By not dismissing these traits as negative but rather understanding how they can be used positively, she could build bridges with Slytherins.
One great example could be 'The Slytherin Connection'. In this fanfic, Hermione starts to bond with Slytherins over a shared love for ancient magic research. Another is 'Green and Brave' where she befriends a Slytherin who is also an outcast in his own house because he doesn't believe in the pure - blood supremacy. There's also 'Snakes and Badgers' which shows how Hermione forms a study group with Slytherins and they gradually become friends as they help each other with their studies.
One common trope is the 'Forced Proximity'. This is where Hermione and Bellatrix are put in a situation where they have to be close to each other, like when Hermione is captured by Bellatrix. It creates a lot of tension and interesting dynamics between the two characters.