One interesting fanfic could be where the Dursleys are secretly magical but have been suppressing it. Maybe in this fanfic, Vernon Dursley has a hidden ability to communicate with magical animals, which he has always feared and tried to hide. This would completely change the dynamic of how they treat Harry as they are also hiding their own secrets.
There might be a fanfic where the Dursleys are different in that they are actually kind to Harry from the start. Instead of the usual abuse and neglect, Petunia takes Harry in as if he were her own son. This could lead to a whole new adventure where Harry grows up with a loving family within the Muggle world and still discovers his wizarding heritage in a different way. He could learn about magic from a more positive Muggle perspective at first.
In some fanfics, the Dursleys could be part of a different magical organization. For example, they could be members of a group that opposes the Ministry of Magic's way of doing things. Dudley might be a key character in this. He could be a powerful young wizard in this fanfic, and his relationship with Harry changes as they both explore this new side of the wizarding world that is outside the normal Hogwarts and Ministry - centric view.
In some fanfictions, the Dursleys might be portrayed as having a change of heart. For example, they could start to secretly admire Harry's magical abilities instead of resenting them. This can add an interesting twist to the original story.
One interesting Dursleys fanfiction could be about Dudley's life after learning the truth about the wizarding world. Maybe he starts to have a change of heart and tries to make amends for how he treated Harry over the years.
Well, the Dursleys were really horrible to Harry. Fans want to see different ways he could have been saved. It also allows for new storylines. For example, if he's saved early, how would his magical development be different? How would his relationships with other characters change? All these possibilities make these fanfics interesting. Also, it gives a chance to explore different magical elements and characters in the context of rescuing Harry from the Dursleys.
One popular 'Harry Potter Saved from Dursleys' fanfic could be 'The Early Rescue'. In this fic, perhaps a powerful wizard discovers Harry's situation much earlier and takes him away from the Dursleys. Another might be 'A Different Start' where a magical creature intervenes and whisks Harry to a safe place away from his cruel relatives. There could also be 'Saved by the Unlikely' where a Muggle with some latent magical ability stumbles upon Harry and saves him from the Dursleys.
A popular type of different Harry Potter fanfic is the 'Dark Harry' or 'Evil Harry' ones. These stories usually deviate from the original heroic image of Harry. It could be due to some major event in his life that turns him towards the dark side. There are also fanfics that are set in a Muggle - only world but still incorporate the magical elements in a more hidden way. For example, Harry could be a street magician who secretly has real magic powers and is on a quest to find other magical beings in the Muggle world.
Mrs. Dursley was Mrs. Potter's sister, but the Dursleys treated Harry Potter badly. They never treated him as their own son, almost abusing him. They hid Harry's magical identity, which made Harry confused about his birth and the magical world in the first book. This kind of bad behavior was mainly psychological damage. Harry Potter and the Sorcerer's Stone was not enough. Everyone, please click to read the novel!
One popular fanfiction might be about the Dursleys' secret past that somehow ties them to the wizarding world in a more complex way. For example, perhaps there was a wizard in their family line long ago that they've been trying to hide. Another could be a story where the Dursleys have a change of heart much earlier than in the original series and start to embrace Harry's magical nature, leading to all sorts of comical and heartwarming situations as they try to understand the wizarding world. And there could be a fanfiction where the Dursleys are forced to face the consequences of their mistreatment of Harry in a more magical and extreme way, like being haunted by magical apparitions that represent Harry's pain.
One interesting fanfiction could be about the Dursleys having a change of heart before Harry goes to Hogwarts. Maybe they start to see the magic in him in a different way and struggle with their newfound feelings of protectiveness. It could show a different side of the usually cruel Dursleys.
A great 'Harry Potter Dursleys fanfic' might explore the Dursleys' backstory more deeply. For example, it could show how Vernon's hatred for magic and strange things developed over time. Or it could focus on Petunia's envy of Lily's magical abilities and how that affected her relationship with Harry. Some fanfics also imagine a scenario where the Dursleys are magically transported to Hogwarts and have to adapt to the magical environment. They would be completely out of their element, and it would be interesting to see how they interact with the students and teachers.
There might be a fanfiction where the Dursleys are actually related to a minor wizarding family in some convoluted way. This discovery could lead to a whole new set of adventures and relationships for them. They could be dragged into a wizarding mystery that forces them to cooperate with Harry and other wizards, which would be a huge change from their usual behavior of trying to avoid all things magical.