One possible plot could be that the magical creatures in the Harry Potter world start to show up in Forks. For example, a hippogriff might fly over the forest near Bella's house, causing chaos among the vampires and werewolves. The wizards from Hogwarts could come to investigate these strange new creatures that seem to have a different kind of magic than what they're used to. Harry, Hermione, and Ron could find themselves in the middle of the vampire - werewolf feud, trying to figure out how to keep the peace and also protect the muggles in Forks from getting too involved in this new magical mess.
A plot could involve a spell gone wrong at Hogwarts that transports some students, including Harry, to Forks. There, they meet the Cullens. The wizards are initially confused by the vampires' abilities and the vampires are intrigued by the magic. Maybe Hermione tries to find a scientific explanation for the vampires' existence while Ron is more interested in the werewolves. They could end up teaming up to fight a common enemy, like a dark wizard who wants to use the vampires' powers for his own evil deeds.
Perhaps there's a prophecy in the Harry Potter world that mentions a 'creature of the night' which turns out to be related to the vampires in Twilight. Harry and his friends then have to travel to Forks to figure out what this prophecy means. When they arrive, they get caught up in the love triangle between Bella, Edward, and Jacob. They also learn about the vampire and werewolf politics. Harry realizes that there are more similarities between his world and this new world than he initially thought, especially when it comes to the idea of different species co - existing and the struggle between good and evil.
One possible plot could be that Harry Potter, during one of his adventures in the Forbidden Forest, stumbles upon a magical portal that transports him to the world where Byakko exists. Byakko, being a powerful and mysterious creature, initially sees Harry as a threat. But as Harry shows his kind heart and magical abilities, they form an unlikely alliance. They could team up to fight a common enemy, perhaps a dark wizard who has also found his way into Byakko's world and is causing chaos there.
Maybe Voldemort has some sort of connection to a powerful criminal in Spiderman's world. Harry and Spiderman team up to stop Voldemort from getting his hands on some high - tech weaponry from Spiderman's universe. Spiderman teaches Harry some of his combat moves, and Harry shows Spiderman some basic spells.
Maybe in the fanfiction, Harry accidentally enters a parallel dimension where Lily is still alive. Here, Lily discovers that Harry is her future son. She might take him under her wing and train him in a different way of magic, one that was perhaps forgotten in Harry's own time. This could lead to Harry having unique powers and a different approach to dealing with the Dark Arts and his enemies.
A plot could involve Sherlock being a wizard all along but not realizing it until he meets Harry Potter. He has been using his logical mind to do what he thought was normal detective work, but it was actually his latent magic powers at play. Together, they could solve crimes in both the Muggle and wizarding worlds, using Sherlock's methods and Harry's knowledge of magic spells and potions.
In this fanfiction, a new teacher arrives at Hogwarts who has a passion for both magic and glee. This teacher decides to start a glee - like club at Hogwarts. Harry and his friends are intrigued and join. They discover that music has a special power in the wizarding world. It can be used to unlock hidden magical abilities. The club then prepares for a big magical glee competition against other magical schools, with each performance having a unique magical twist.
Well, perhaps Byako is a being from another dimension. In the 'Harry Potter meets Byako fanfiction', Byako could accidentally cross over into the Harry Potter universe while being chased by some sort of other - dimensional foe. Harry and his friends could help Byako hide from this enemy while also learning about different forms of magic from Byako's world.
Perhaps in the fanfiction, the Ministry of Magic mistakes Loki for a powerful dark wizard. They try to capture him, but Loki easily evades their attempts. Harry Potter, being curious, decides to find out who this strange wizard is on his own. When they meet, Loki is initially hostile, but as they start to talk, they realize they both have a lot in common in terms of fighting against powerful and often misunderstood forces. They then form an uneasy alliance to face a new threat that is emerging in both their worlds.
One possible plot could be that Lady Hogwarts is a long - lost magical being who has been dormant for centuries. Harry Potter discovers her during one of his adventures in the Forbidden Forest. She has the power to manipulate the very essence of Hogwarts itself. Harry, with his inquisitive nature, tries to learn from her about the ancient magic that she holds, and together they face a new dark threat that is emerging from the shadows of the school's past.
One possible plot could be that Harry Potter is somehow transported to the world of Samurai Jack. He teams up with Jack to fight Aku. Harry uses his magic, like the Patronus charm to fend off Aku's dark minions, while Jack uses his sword skills. Their combined powers and different fighting styles make them a formidable duo against Aku's tyranny.
Well, in a 'Harry Potter meets Hunger Games' fanfiction, a cool plot could be that the Ministry of Magic decides to hold a tournament inspired by the Hunger Games to choose the most powerful wizard among the young generation. The champions from different wizarding schools are magically transported to a large, enchanted forest where they have to face both magical creatures and traps while also competing against each other using spells and potions. Harry Potter and his friends could be among the champions, and they would have to use their wits and friendship to outsmart the others.