One idea could be a story where Newt Scamander's magical beasts escape into Hogwarts. The students and teachers have to work together with Newt to recapture them. It would be a chaotic yet fun scenario as the beasts interact with the Hogwarts environment and its inhabitants.
Perhaps a fanfic where a young Harry Potter meets Newt in his early years. Newt could teach Harry about some of the more obscure magical creatures, which would later help Harry in his battles against Voldemort. This could add a new dimension to Harry's knowledge and skills.
One idea could be that Newt Scamander visits Hogwarts to give a special lecture on fantastic beasts. During his visit, he discovers a hidden magical creature that has been living in the Forbidden Forest for centuries. Harry Potter and his friends get involved in helping Newt study and protect this new discovery.
One idea could be exploring the backstory of a minor character from the series in the fanfiction. For example, delving into the early life of Luna Lovegood's father. Another could be a story where a new magical creature is discovered in the Forbidden Forest and how the Hogwarts students interact with it. Or perhaps a fanfiction where the events of the Fantastic Beasts movies intersect more directly with the main Harry Potter storyline, like Newt Scamander visiting Hogwarts during Harry's time there.
One idea could be a crossover with the Harry Potter universe. For example, Newt Scamander could meet Harry and his friends and they could go on an adventure together to find a new and extremely dangerous fantastic beast that has escaped from Newt's case. Another idea is a crossover with a historical fantasy world, like Camelot. Newt could travel to Camelot and help King Arthur's court deal with a magical beast that is terrorizing the kingdom.
Friendship is a common theme. Just like in the original series, characters from both universes form bonds to face challenges together. For instance, Harry and Newt might become friends and rely on each other's unique skills.
One idea could be a spell gone wrong in the wizarding world that somehow transports some Hogwarts students to Forks. They then have to deal with the vampire and werewolf situation there while also trying to find a way back home. Maybe Hermione could be intrigued by the science - like aspects of the Twilight world that seem so different from magic.
One idea could be that the characters from 'The Magicians' end up at Hogwarts for a magical exchange program. They'd have to adapt to the different magical rules and culture there. For example, Quentin might be fascinated by the concept of houses at Hogwarts, while Eliot could get into trouble for trying to introduce some of his more 'adult' magic tricks from Brakebills.
One idea could be that Chuck, with his knowledge of the supernatural, ends up at Hogwarts. Maybe he's there to investigate some strange magical occurrences that are linked to his world's demons or angels. He could form an unlikely friendship with Harry Potter, and together they figure out how to stop a dark force that's using both magic and the powers from Chuck's universe.
One idea could be that Voldemort discovers the Infinity Stones and tries to use their power to conquer both the wizarding world and the Muggle world. The Avengers, with the help of Harry Potter and his friends, must stop him. They could combine magical spells with superhero powers to create unique battle strategies.
One idea could be that Voldemort teams up with a powerful Marvel villain like Thanos. This would force the Avengers and the Harry Potter characters to join forces. The Avengers could bring their strength and high - tech weapons, while the Harry Potter characters use their magic. Another plot could be that a magical artifact from the Harry Potter world is lost in the Marvel universe and both groups have to search for it. Maybe it has the power to destroy both universes if misused.
One idea could be that Voldemort somehow makes an alliance with Loki. The Avengers would then have to team up with Harry, Hermione and Ron to stop them. They could combine magic and superpowers in battles. For example, Iron Man could use his technology to analyze and counter some of the dark magic spells while Harry uses his Patronus to protect the group from Loki's illusions.