One idea could be that Severus, with his potions expertise, is recruited by the Bond - like organization in a world where magic and espionage co - exist. Harry, being a key figure in the wizarding world, gets involved too. Maybe they have to work together to stop a dark wizard who is collaborating with a group of evil non - magical villains.
Perhaps Severus and Harry are sent on a mission to infiltrate an enemy base that is protected by both magical and technological means. Bond - style gadgets and wizardry combine as they face numerous challenges. Harry uses his Gryffindor courage and Severus his Slytherin cunning to get through the various traps and enemies.
One possible plot idea could be Harry growing up with a conflicted identity. Since Tom is often associated with dark magic and Severus has his own complex past, Harry might struggle to come to terms with his heritage. He could be shunned by some in the wizarding world who fear his connection to Tom.
Severus would be his usual brooding and sarcastic self. His distrust of others might initially cause friction with Bond, who is used to working in a team. Harry, on the other hand, would be more open - minded. He might be in awe of Bond's suave and confident nature at first. But as they get to know each other, Severus would start to respect Bond's skills and Bond would come to understand Severus's complex past and motives.
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.
Well, for a Harry Potter and Naruto crossover fanfic, a cool plot could be that there is a dark force emerging that is a combination of Voldemort's magic and the Akatsuki's evil intentions. Harry Potter and Naruto then join forces. They start by training together, with Naruto teaching Harry some basic ninja moves like tree - walking to improve his physical abilities, and Harry teaching Naruto some basic spells for protection. Along the way, they gather their friends from both worlds, Hermione and Sasuke for example, to fight against this new threat.
One idea could be that the Avatar characters gain the ability to use magic when they enter the Harry Potter world. For example, Aang could use his airbending skills along with magic spells to fight against the Death Eaters. Another could be that Hogwarts students are sent to the Avatar world for a special exchange program, and they have to learn to bend elements instead of casting spells.