One possible plot is that Hagrid rescues Harry from the Dursleys right after he gets his Hogwarts letter. Hagrid takes Harry to Diagon Alley immediately, and Harry starts exploring the wizarding world without having to endure more time with the Dursleys. He could then make friends with other young wizards and witches outside of Hogwarts before starting school, which would change his Hogwarts experience.
Well, it could be that a group of rogue wizards, who are actually good - hearted but don't follow the Ministry's rules strictly, rescue Harry. They see how the Dursleys are treating him and decide to take matters into their own hands. Harry then gets to learn a different kind of magic from them, a more unorthodox style. This could lead to him having unique abilities when he finally enters Hogwarts, and he might have a bit of a conflict with the Hogwarts faculty at first because of his different magical upbringing.
In this kind of fanfiction, perhaps Harry is rescued by the Order of the Phoenix earlier than in the original story. They might have realized the Dursleys' mistreatment sooner. Then Harry could start his magical training earlier, away from the hostile environment of the Dursleys' home. He may also form closer bonds with other members of the Order, like Sirius, who could play a more active role in his upbringing.
Hermione could be the rescuer. Maybe she discovers through her research that Harry is in a bad situation at the Dursleys' and decides to take action. She uses her intelligence and magic skills to break into the Dursleys' house and get Harry out. Then they would go on an adventure together, and Hermione would be like a mentor to Harry in a way, teaching him things she has learned from books.
Perhaps Harry sues the Dursleys for false imprisonment. He realizes that all those years of being confined to his room or the cupboard were illegal. He enlists the help of Hermione, who is well - read in both wizarding and Muggle laws. They present a strong case against the Dursleys. As a result, the Dursleys face public humiliation in their neighborhood, and Harry finally gets the justice he deserves, while also starting to heal from the trauma of his childhood.
Perhaps Harry uses his influence among his friends. Hermione could help him find some loophole in the Muggle - wizarding laws regarding property. Ron might provide some comical support, like trying to use some half - baked spell to make the Dursleys uncomfortable enough to leave. In the end, Harry evicts them and takes over the house, turning it into a place that's more welcoming for himself and his wizarding friends when they visit the Muggle world.
One possible plot could be that the Dursleys, out of their long - held hatred and envy, finally find a way to use dark magic against Harry. Maybe they make a deal with some dark wizards who provide them with a powerful curse. They manage to cast it on Harry when he's at his weakest moment, perhaps during one of his vacations at Privet Drive.
In this fanfiction, perhaps the Dursleys' constant abuse and neglect cause Harry to have some sort of mental or physical disability. It might show how he has to overcome not only the challenges of the wizarding world but also the trauma inflicted by his Muggle relatives. For instance, he could have problems with his legs from being locked in a cupboard for long periods, which would be a physical crippling, and then have to deal with the self - doubt and fear that comes with it.
If Harry Potter died at the Dursleys, it would be a huge shock to the magical community. First, the Dursleys, who had always resented Harry, would suddenly find themselves in a very difficult situation. They were supposed to protect Harry, but his death would surely draw the attention of the Ministry of Magic. In fanfiction, this could lead to investigations into the Dursleys' treatment of Harry. Magically, the protection that Harry's mother's sacrifice provided might be broken in a different way. And Voldemort, unhindered by Harry, could start to reshape the wizarding world according to his dark desires much more quickly.
In some Harry Potter fanfictions, the Dursleys are depicted as nice. This could be a really interesting take. It might show how they could have been different if they hadn't been so influenced by their dislike for magic. Maybe they could have supported Harry more, or at least been less cruel. For example, a fanfiction could explore a scenario where Vernon Dursleys actually encourages Harry's academic achievements at school, instead of always putting him down.
One way the Dursleys can be good in fanfiction is if they are forced to face the consequences of their actions early on. For instance, they might receive a warning from the wizarding world that if they don't treat Harry well, there will be serious repercussions. So they start to be nicer to him. They could provide him with a proper room, better food, and allow him to have friends over.
The plot could involve the goblins rescuing Harry when he is being wrongly accused of a crime in the wizarding world. They could believe in his innocence and use their unique skills and knowledge of magic to keep him safe. Maybe they help him prove his innocence later on. They might also have their own motives for helping Harry, like they see him as a key to some sort of change in the relationship between wizards and goblins.
One possible plot could be that Harry is wrongly accused of a crime in the wizarding world, perhaps something related to dark magic. The police, who might be a new magical law enforcement unit, rescue him from an angry mob. They then help him clear his name by finding the real culprit, who could be a Death Eater in disguise trying to frame Harry to cause chaos in the post - Voldemort era.