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.
The plot could revolve around the descendant having to prove their worthiness as a Gryffindor. They face a series of challenges set by the Sorting Hat, which has been enchanted by Gryffindor long ago. These challenges test their courage, loyalty, and nerve, much like Harry and his friends faced in the original series.
Perhaps an ancient evil that Gryffindor once sealed away is starting to break free. This entity sees the descendant as a threat because they have the potential to reseal it. So, it tries to corrupt the descendant or stop them in any way possible.
A plot could be that a Gryffindor Animagus accidentally reveals their form during a Quidditch match. This causes chaos as everyone tries to figure out who it is. It also draws the attention of the Ministry of Magic who have strict rules about unregistered Animagi. The character then has to deal with the consequences while also trying to prove they mean no harm.
Yes, often there are. For example, the main character as a descendant of Merlin might have unique magical powers. They could be able to perform spells that are long forgotten or have an innate understanding of ancient magic. This can lead to all sorts of adventures, like exploring hidden chambers in Hogwarts that were sealed by Merlin himself and uncovering secrets that could change the wizarding world.
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.
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.
One plot idea could be that Harry discovers his heritage as the heir of Godric Gryffindor early on. This could lead to him having special powers or abilities that are associated with Gryffindor. For example, he might be able to communicate with the portraits of Gryffindor more easily and gain wisdom from them. Another idea is that there could be a hidden treasure or weapon left by Gryffindor that only his heir can find and use to defeat Voldemort. It could also involve a quest where Harry has to prove his worthiness as the heir by facing various challenges that test his Gryffindorian traits like courage, chivalry, and determination.
He might seek refuge in another house. For example, he could try to convince the Hufflepuffs to take him in. The Hufflepuffs, known for their acceptance, might be his best bet. This could lead to a whole new set of relationships and storylines as he adjusts to a different house environment.
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.
It would probably explore family ties. For example, how the Weasley family would react to the discovery. There might be a whole new level of acceptance and closeness. Also, it could explore the idea of hidden family magic that only comes to light because of Harry's new connection.
One possible plot twist could be that the sword has a hidden power that only activates when in the hands of a true Gryffindor with a specific intention, like uniting all the houses against a new, unexpected dark force. Another could be that the sword was actually created with a part of Godric Gryffindor's soul, similar to a Horcrux but in a positive way, and it gives the wielder special insights into Gryffindor's thoughts and strategies.