Perhaps the fanfiction could start with a mysterious event that makes all communication spells in the wizarding world fail, just like how communication systems failed during 911. This leads to chaos as people can't call for help. Harry Potter then embarks on a journey to find out what's causing this. Along the way, he discovers that a powerful and ancient magic artifact has been corrupted and is causing this disruption. He teams up with his friends and some new allies to repair the artifact and restore order in the wizarding world. During this process, they face many challenges and also learn more about the history and power of magic in their world.
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.
Maybe Harry could be the host of the Kyuubi's power in the wizarding world. He would have to deal with not only the threats from Voldemort but also the power of the Kyuubi inside him. His friends might be both amazed and a bit scared of this new power source.
Well, it could be about Harry Potter somehow taking on the characteristics or abilities of Alastor Moody. Maybe he has to pretend to be Moody for a mission and in the process, he learns a lot about Moody's past and his way of dealing with dark wizards.
One possible plot could be that Harry, after the war, decides to pursue baking as a form of therapy. He starts a small bakery in Hogsmeade and uses his magic to create unique baked goods. His friends come to support him, and he ends up using his baking to bring the wizarding community closer together.
One possible plot could be that Sauron somehow manages to enter the wizarding world. Maybe through a powerful dark magic spell that links the two universes. Harry, being the hero, senses the new and greater evil. He then has to figure out how to defeat Sauron, which is much more difficult than any foe he has faced before. He might have to learn about the power of the One Ring and how to destroy it, all while protecting Hogwarts and the wizarding world from Sauron's dark minions.
The plot might involve a crossover where the magical world of Harry Potter collides with the concept of balverines. Maybe Harry and his friends encounter balverines during one of their adventures outside of Hogwarts, and they have to use both their magic skills and newfound knowledge about balverines to survive.