It could be an elf that was previously unheard of, like a descendant of a long - lost line of house - elves.
The 'harry potters new house elf master story' could revolve around the idea of Harry taking on the role of a master to a house - elf. This new relationship might bring a lot of changes to Harry's life at Hogwarts. The house - elf could introduce Harry to a whole new world within the wizarding community, like secret places or forgotten spells. There could also be a conflict where the elf's loyalty is tested, and Harry has to prove himself as a worthy master. This could lead to a series of events that not only strengthen their bond but also help Harry in his overall journey as a wizard.
There could be many possibilities. It might be an original character created specifically for the fanfiction. However, it could also be a well - known house - elf from the original series, like Dobby, who in the fanfiction somehow comes to be owned by Harry Potter in a different set of circumstances. Maybe Harry saves Dobby in a more complex way in this fanfiction and as a result, Dobby becomes his house - elf.
Dobby is often very popular in fanfiction. Since he was already a rather unique and brave house - elf in the original series, in fanfiction he can be portrayed in even more heroic or complex ways, like leading a revolution among house - elves.
Well, perhaps the house - elf is constantly tidying up in really cool ways. It could be folding clothes by magic so that they are always perfectly creased, or it might arrange the books in Harry's library in a way that makes it easier for him to find the exact spell book he needs at any given time. And it could also have a special connection with the other magical creatures around the house, like communicating with the garden gnomes and getting them to stay in line without causing trouble.
Dobby is definitely one of the most popular. His character from the original books was so endearing and his actions so brave that he often features prominently in fanfiction. Another popular one is Kreacher. His complex relationship with the Black family and his growth as a character make him a great subject for fanfiction writers.
One common theme is the exploration of the house - elf culture. Since Harry is in the role of a house - elf, the fanfic often dives deep into how house - elves live, their loyalty to wizarding families, and their magic. For example, how Harry might adapt to the different types of magic that house - elves use.
Another possibility is a group of Hogwarts professors who are very conservative in their views. They might believe that house elves should remain in their subservient positions and would try to stop Harry from making any changes. They could use their influence within the school to make things difficult for Harry and her friends as they try to advocate for the rights of house elves.
Maybe Harry Potter, as a female, could start to understand the struggles of house elves deeply. She might use her magic to try and improve their living conditions, like Hermione did with the 'Society for the Promotion of Elfish Welfare'. She could also form unique friendships with some house elves, leading to adventures within Hogwarts and beyond as they work together to change the traditional views of house elves in the wizarding world.
Well, perhaps Harry could start seeing the world from the house - elves' perspective. He might use his magic in new ways to improve their living conditions. For example, he could secretly create better living quarters for them in Hogwarts. He might also try to teach them some basic self - defense magic so they can protect themselves from the meaner wizards.
I'm not sure about a specific one titled exactly like that, but there are many fanfics where Harry has some sort of connection to the house - elf world. You could try searching on fanfic platforms like Archive of Our Own. There, you might find some great stories that explore this concept, maybe even some where Harry is magically transformed into a house - elf and has to deal with the discrimination and unique culture of house - elves.