In a fanfiction, Rose could be a descendant of a powerful wizard family. Harry Potter discovers her potential and decides to train her. Dobby becomes Rose's helper, making sure she has everything she needs during her training. The story could focus on Rose's growth as a witch, with Harry as her teacher and Dobby as her loyal supporter.
One idea could be a story where Rose, who might be a new student at Hogwarts, befriends Dobby. Harry Potter could then play a role as a mentor to Rose, guiding her through the magical world. Dobby could use his unique magic skills to help Rose in various tasks around the school, like finding hidden passages.
They could be in a time - travel scenario. Harry Potter accidentally takes Rose and Dobby back in time. They have to work together to get back to their own time. Dobby's house - elf magic might be crucial in finding a way back, while Rose uses her modern - day knowledge of magic (maybe she's read a lot about old magic) to help them along, and Harry Potter uses his experience from his own adventures.
At first, Harry might be a bit annoyed by Dobby's antics. But as the story progresses in the fanfiction, he could notice Dobby's good intentions. Dobby's eagerness to serve and protect Harry could touch Harry's heart. Maybe Dobby saves Harry from a particularly dangerous situation that makes Harry see Dobby in a whole new light. Harry then starts to admire Dobby's tenacity. He may also be intrigued by Dobby's strange habits, like his obsession with odd - looking socks. This new - found admiration could lead to Harry becoming a big fan of Dobby.
In such a fanfiction, it could lead to Harry having a more loyal and protective companion. Dobby's magic and determination might aid Harry in unexpected ways.
One idea could be a crossover where Fenrir from the Harry Potter universe somehow gets transported to the realm of Loki. Loki, being the trickster, might see Fenrir as a tool for his own schemes. Harry Potter, perhaps in a quest to stop some dark magic related to Fenrir, ends up following him and has to deal with Loki's antics as well.
Maybe in a fanfiction, Medusa is a distant relative of one of the magical creatures in the Harry Potter universe. Harry, Ron and Hermione discover this connection during their research for a class project. They then go on an adventure to find out more about Medusa and how her powers could be related to some of the dark magic they've encountered.
Perhaps a fanfiction where the Basilisk is not a solitary monster but part of a larger, more complex ecosystem in the Chamber of Secrets. There could be other magical creatures that depend on the Basilisk in some way, and when the Basilisk is in danger, these other creatures come to its aid. This would change the whole dynamic of how the characters interact with the Basilisk and the Chamber of Secrets.
One idea could be a story where Hermione and Draco are paired up for a special project at Hogwarts. They start off hating each other as usual, but as they work together, they begin to understand each other better. Harry could be suspicious at first, but then realizes that their newfound friendship could be beneficial for the wizarding world. For example, Draco might share some Slytherin secrets that help in a battle against the dark forces.
One idea could be that Lilith Lemon is a new student at Hogwarts who has a mysterious past. She meets Harry Potter and they end up on an adventure together to uncover a hidden magic within the school. Maybe she has a special ability related to divination and helps Harry foresee some upcoming danger.
One idea could be a story where Dudley and Piers start to see Harry in a new light after he saves them from a magical threat in the Muggle world. They then become sort of secret allies to Harry, helping him out when he's in the Muggle neighborhood.
One idea could be a time - travel fanfiction where Hermione goes back in time and has to face Bellatrix in a magical duel. Harry could be caught in the middle, trying to protect Hermione. Maybe Bellatrix has a secret that could change the course of the wizarding war, and Hermione discovers it.