One possible plot could be that Harry is framed for something he didn't do. Maybe a powerful dark object is found in his dorm, and the Gryffindor house, fearing for their reputation and safety, decides to exile him. Harry then has to prove his innocence while also dealing with the isolation and new challenges outside of his familiar house.
Perhaps there's a misunderstanding within Gryffindor. A prophecy is misinterpreted to suggest that Harry will bring doom to the house. So, they exile him. As a result, Harry has to find new allies among the other houses or even among the outcasts of Hogwarts. He might discover new magical abilities or secrets in his quest to clear his name and get back to Gryffindor.
One possible reason could be a false accusation of using dark magic. In some fanfictions, the wizarding world can be very paranoid about dark magic, and if Harry was wrongly suspected of delving into it, Gryffindor might exile him to protect their reputation.
A dark force that has the ability to influence the minds of Gryffindor members. This could be a powerful and ancient magic or a new form of dark magic. It turns the house against Harry without them fully realizing it, making the collective Gryffindor house, under this influence, seem like the antagonist.
He would probably be extremely hurt. Gryffindor was like his family at Hogwarts, so being exiled would be a huge blow. He might initially feel angry and betrayed.
In a 'Harry Potter betrayed by Gryffindor' fanfiction, perhaps there is a prophecy that is misinterpreted. The Gryffindors think Harry is the cause of upcoming doom instead of the savior. So, they begin to betray him. Harry would then have to struggle not only with the external dark forces but also with the internal pain of being rejected by those he considered friends and housemates. He might start to question his own identity and values, and his journey would be about regaining the trust of Gryffindor or finding his own path without them.
Well, it could be about Harry struggling to fit in with the typically bold Gryffindors. Maybe he has a hard time speaking up in class or during Quidditch matches. He might have a small group of close friends who help him come out of his shell.
One interesting plot could be that the descendant discovers a hidden chamber in Hogwarts that was sealed by Gryffindor himself. Inside, there are ancient spells and secrets that could change the wizarding world. The descendant has to battle dark forces who also want to get their hands on these secrets.
Yes, in some fanfictions, Harry Potter is depicted as the heir of Gryffindor. It adds an interesting twist to the original story. The connection to the Gryffindor sword becomes more profound as it is often a symbol of Gryffindor's legacy. In these fanfictions, Harry might discover hidden powers or a deeper understanding of his destiny through this new identity.
There could be several reasons. One is simply to add drama. A lot of fanfiction writers thrive on creating conflict, and what better way to do that than by taking on one of the most beloved houses in the 'Harry Potter' series? Another reason might be personal bias. Perhaps the writer had a negative experience with someone who identified strongly with Gryffindor, or they just don't like the traits that are typically associated with Gryffindor, like impulsiveness, and they use fanfiction as a way to express their views.
One great 'Harry Potter Gryffindor Fanfiction' is 'The Gryffindor Princess'. It has a really interesting plot where a new student arrives at Hogwarts and is sorted into Gryffindor, but she has a mysterious past that ties into the original story in unexpected ways.
There could be a fanfiction where a Gryffindor Animagus is trying to find out more about their ability. They might search through the restricted section of the library. In their Animagus form, they could access areas that are hard to reach for normal students. And they might meet other magical creatures who can guide them in understanding their powers better.