They are popular because the Dursleys are such complex and disliked characters in the original series. Fanfictions give readers a chance to explore their motives and potentially redeem them. For example, we can understand why they treated Harry so badly in some fanfictions which might be due to their fear of the unknown world of magic.
The Dursleys are a contrast to the magical world of Harry Potter. Fanfiction writers like to play with this contrast. They can create stories where the Dursleys are dragged into the magical world, and seeing their reactions to things like spells and potions can be very entertaining. It's like taking characters from a very ordinary, dull world and throwing them into a world full of wonder and mystery.
Another reason is that there are so many untold stories about the Dursleys. In the original books, we mainly see them through Harry's eyes. Fanfictions allow us to see their perspective. For instance, what was going on in their minds when they first received Harry? What if they had some secret knowledge about the wizarding world that they were hiding? These possibilities make the Dursleys fanfictions appealing to many fans.
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.
The popularity also lies in the fact that Lily represents a great deal of love and sacrifice in the Harry Potter universe. Fans like to explore how that love would have directly affected Harry as he grew up. They can create stories where Harry gets to know his mother better, and it gives a more complete family dynamic that was missing in the main series. Also, it allows for different interpretations of Lily's character and her magic, which is always interesting for fans to read about.
They're popular because it gives readers a different perspective on Harry's character. Instead of the typical Hogwarts - bound, often restricted Harry, an emancipated Harry has more agency. It allows for new storylines that deviate from the original and can be more exciting.
They're popular because they add a new layer of depth to the characters. We get to see how the beloved 'Harry Potter' characters handle pain and adversity, which makes them more relatable.
Another reason is that Ginny herself is a very interesting character. She's strong, independent, and has her own story. Fanfictions that focus on Harry and Ginny can give more spotlight to Ginny's character and how she complements Harry. This combination of two beloved characters in different and creative storylines is what makes these fanfictions so appealing to a wide range of Potter fans.
They're popular because it's fun to see a different side of Harry. In the original books, he had his struggles, but in these fanfictions, he's often in control. It gives a sense of power and satisfaction to the readers.
Another reason is that it gives a chance to explore different 'what - if' scenarios. What if a character had made a different choice 19 years ago? How would that have changed the present? Fanfiction writers can play around with these ideas, which is really appealing to fans. Also, seeing the growth and development of the original characters' children or the further development of the wizarding world is exciting for fans who have a deep connection to the 'Harry Potter' universe.
They're popular because Sirius is a very complex and beloved character. His story in the original books is full of tragedy and mystery, so fanfiction writers can explore different aspects of his character, like his relationships or his unfulfilled potential.
Because many fans feel that Harry was mistreated by the Dursleys in the original story. So they create fanfictions where he is taken away from that bad situation. It gives Harry a chance at a different and hopefully better life.
The popularity also lies in the fact that it can expand on the relationships within the Potter family. We can see how Lily Luna interacts with her father, Harry, and her siblings. Fanfiction writers can create heartwarming or action - packed stories around these relationships, which appeals to a wide range of 'Harry Potter' fans.