Perhaps the fanfiction could focus on Harry missing his parents during his first Christmas at Hogwarts. He then discovers a hidden room in the castle that has remnants of past Christmas celebrations. There, he finds a photo album that shows his parents' Christmases at Hogwarts, which gives him a feeling of connection to them.
In this fanfiction, Harry could be involved in a Christmas mystery. There are strange happenings around the school during the holidays. He, along with his friends, investigates and uncovers that it's a group of mischievous house - elves trying to create a truly unforgettable Christmas for the students of Hogwarts. They end up joining in the fun and having a great time.
Well, it could be about a vampire who has been hidden in the wizarding world for a long time and Harry Potter is the first to discover it. Maybe this vampire has some unique powers or knowledge that could help Harry in his fight against Voldemort.
Well, it could be about Harry Potter somehow finding a Pokémon in the wizarding world. Maybe a Pokémon gets magically transported there, and Harry has to figure out what it is and how to deal with it.
Maybe Harry Potter sees a first - year student who is an orphan or in a difficult situation. He decides to take the student under his wing. He could teach the first - year all about Hogwarts, from the secret passages to how to deal with bullies like Draco. They might also have adventures together, exploring the Forbidden Forest or solving mysteries within the castle.
Obviously, Harry Potter himself would be a main character. He is the heart of any Hogwarts - related story. Also, Ron Weasley and Hermione Granger, as they are Harry's closest friends and would surely be part of his first Christmas at Hogwarts.
The plot could involve a situation where a new form of dark magic is unleashed in the wizarding world, which spreads like wildfire and causes destruction similar to 911. The Ministry of Magic is caught off - guard. Hermione, with her vast knowledge, starts researching a way to counter this magic. Meanwhile, Ron and Harry lead the effort to protect the civilians. They set up shelters in places like the Room of Requirement and use Patronuses to guide people to safety. As they dig deeper, they discover that this dark magic was a planned attack by a long - hidden dark wizard group who wants to take over the wizarding world.
One possible plot could involve a group of spiders that have been enchanted by a dark wizard. These spiders start attacking Hogwarts students. Harry, along with his friends Hermione and Ron, would need to find the source of the enchantment and break it to save the school. They might have to explore the Forbidden Forest more deeply and face their fear of spiders to do so. This would combine the elements of adventure, mystery, and the existing spider lore from the Harry Potter series.
The plot could involve Catwoman being drawn into the wizarding world by some mysterious magical force. She might start out as an outsider, trying to figure out how things work. Maybe she gets involved in a plot to steal a powerful magical object, but along the way, she starts to have a change of heart and decides to help the good guys instead.
A plot could be that Gaster has a connection to the Forbidden Forest in Harry Potter. He might be the source of some of the strange and dangerous creatures there. As Harry and his friends explore the forest more, they start to notice Gaster's influence. Gaster could also be using the forest as a way to try and get back to his own world or to gain power in the Harry Potter universe. This would lead to a series of adventures and battles as the characters try to either stop Gaster or understand his motives.
In this fanfiction, the plot could center around Harry Potter arriving in Tamriel during a time of great unrest. He discovers that there are parallels between the magical hierarchies in Tamriel and Hogwarts. He could get involved in the political struggles of the various factions in Tamriel while also trying to find a way back home. Along the way, he might teach some of the Tamriel mages about some of the more advanced magic he learned at Hogwarts, like Patronus Charms, and in return, learn about Tamriel's unique magical artifacts and how to use them.
One possible plot could be that Harry discovers that the wizarding world was actually created by androids in the far future as a sort of historical experiment. So he has to use his magic skills to break free from the control of these androids who are now trying to manipulate the wizarding world for their own purposes.