A possible plot twist could be that Hermione is a half - veela. This is not related to being a Muggleborn at all. The fanfiction could show how her veela heritage affects her magic and her relationships at Hogwarts. For example, it might make her more alluring and powerful in certain types of magic, like charms. This would completely change the way her character is typically portrayed in the original stories where she was thought to be a Muggleborn.
In some of these fanfictions, a great plot twist is that Draco, being a Muggleborn, is actually a long - lost heir to a powerful Muggle - related magical artifact or prophecy. This throws the whole wizarding world into chaos as different factions try to either use him or protect him. Also, there could be a plot twist where Draco uses his knowledge of the Muggle world to outwit dark wizards. Since he has a connection to the Muggle world that most pure - bloods don't, he can come up with strategies that are completely unexpected, like using Muggle technology in a magical way to defeat his enemies.
One interesting plot twist could be that Hermione, as a Gryffindor in the original series, starts to question the values of her own house because of her newfound admiration for Slytherin. Maybe she discovers a long - lost family connection to a Slytherin family, which makes her more empathetic towards their ways. Another could be that she uses Slytherin - like cunning to solve a problem that Gryffindor bravado couldn't handle, causing a rift between her and some of her Gryffindor friends.
One interesting plot twist could be that Hermione's real family is a powerful wizarding dynasty in hiding. For example, they might have been in hiding from a dark wizard who was after their unique magical abilities. Another could be that she was adopted to protect her from a prophecy related to her future powers. Maybe she discovers that she has a connection to an ancient magical artifact that only her real family knew about, and this discovery changes her whole perspective on her identity and place in the wizarding world.
In some of these fanfictions, a great plot twist is when Hermione's switch to Slytherin causes a rift among her old Gryffindor friends. However, this rift actually leads to a deeper understanding between the houses in the long run. She might also start to question the values she was taught in Gryffindor and find that Slytherin has some values, like ambition in a positive sense, that she can really embrace. And there could be a plot where she has to use her new - found Slytherin knowledge to save Hogwarts from a threat that Gryffindor - centered magic couldn't handle.
Well, sometimes in these fanfictions, a plot twist is that the Prewett twins are actually under a hidden curse. Hermione, being the brilliant witch she is, has to figure out how to break it. And it turns out that the curse is related to an ancient magic that has been long forgotten. This leads to a whole adventure where they have to search for clues in the Forbidden Forest and old wizarding libraries.
In some of these fanfictions, a great plot twist is when Hermione gets cursed and Draco has to find a way to break it. During this process, they learn more about each other's true selves. Also, it could be that Draco is under the influence of a dark spell that makes him act against Hermione, but she believes in the good in him and tries to break the spell, which deepens their bond in a very unexpected way.
One great plot twist could be that Hermione is actually an undercover Auror in a world where the Ministry is corrupt. She has to pretend to be on their side while secretly gathering evidence against them. This adds a layer of mystery and danger to the story.
In some fanfictions, a great plot twist is that Snape is not really who he seems in terms of his magical abilities. He might be hiding a much greater power, and Hermione discovers this during a crucial moment. This discovery makes her trust in him even stronger as she realizes he has been hiding his true self not to intimidate others but to protect the wizarding world in his own way. Also, there could be a twist where Snape and Hermione are the only ones who can access a powerful, ancient magic, and this shared ability and the secrets it holds lead to a deeper level of trust between them.
One interesting plot twist could be that Hermione and Harry discover their relation much later in their Hogwarts years. Maybe they've always had a special bond but just attributed it to their friendship. Another could be that their shared heritage gives them unique magical abilities that no one else has, like a combined spell -casting power that can defeat the darkest of dark wizards.
One possible plot twist could be that Hermione discovers a hidden power within herself that is not in the original books. For example, she might find out she has a special connection to an ancient magic that only warriors possess. This could change her role in the wizarding world completely and lead her on a new adventure to master this power.