One possible interesting plotline could be the Rose Child having unique magical abilities that are different from the regular magic in the Harry Potter world. For example, they might be able to communicate with a special kind of magical creature that others can't.
Perhaps the Rose Child has a connection to an ancient magic that was long forgotten in the wizarding world. This could lead to a series of adventures where they have to discover the secrets of this magic and how it can be used to either save or endanger the wizarding community. They might find clues in old, dusty tomes in the Hogwarts library or from the memories of very old wizards and witches.
Well, perhaps the child in the 'Harry Potter child in Azkaban' fanfiction forms unexpected alliances. Maybe they team up with some of the inmates who have their own reasons to oppose the unjust system of Azkaban. This could lead to a series of adventures where they try to break free from Azkaban's clutches together.
Perhaps a plotline where Harry discovers other immortal beings. He could form a sort of community with them, learning about different cultures and powers that immortality has bestowed upon them. They might teach him how to better control his immortality, like hiding his true nature from mortals or using his extended lifespan to gain knowledge that no one else has. This could lead to adventures as they try to protect their secret from those who would seek to exploit it.
One possible plotline could be the discovery of the secret child and how it affects Harry's relationships with his friends and family. For example, Hermione and Ron might be shocked at first but then become supportive. Another could be the challenges the child faces growing up in the wizarding world with this secret hanging over them.
In some Harry and Ginny Cursed Child fanfictions, the plot could revolve around their children. Ginny might notice some strange behavior in their kids that she suspects is related to the Cursed Child's influence. She then teams up with Harry to investigate. They could find out that there are some latent magical powers in their children that are being affected by the dark magic from the Cursed Child's events. This could lead to a series of challenges and adventures as they try to help their children and safeguard the wizarding world.
In some 'Harry and Draco secret child fanfiction', there could be a plotline where the child serves as a bridge between the two families. Harry's side, like the Weasleys, and Draco's family might initially be against the idea of the child. But as the story progresses, the child's presence changes their perspectives. The child might also struggle with its own identity, being part wizard from two very different backgrounds, and this internal struggle could be a central part of the story.
Well, there might be a plotline where the gamer - inspired character creates their own magical guild within Hogwarts. They recruit other students based on their unique magical skills, much like forming a team in a game. Together, they embark on quests to find hidden magical artifacts that could change the balance of power in the wizarding world. This not only adds a new dynamic to the familiar Hogwarts setting but also brings in the cooperative and competitive elements often found in games.
Another plotline could involve the amulet having the power to travel through time. Harry uses it to go back in time to learn more about Voldemort's past, in order to find a weakness. This would be a very exciting and complex story, as he would have to be careful not to change the present too much while in the past.
One interesting plotline could be the emancipation of house - elves in a more radical way. Maybe a group of wizards and witches, inspired by Hermione's SPEW, take more forceful actions to give house - elves full rights and freedom, which could lead to a lot of conflicts with the traditional pure - blood families who are used to having house - elves serve them.
One interesting plotline could be a jumper that has special powers. For example, it might be able to transport the wearer to different magical locations in the Harry Potter universe. Another could be a jumper that changes its appearance based on the wearer's mood or the magical situation around them.
Some fanfictions might explore the political power struggle between different pure - blood families. They could show how these families vie for influence within the Wizengamot. It's like a game of thrones in the wizarding world, with each family using their own strategies to gain more power and control over magical policies.