Well, perhaps the Enterprise crew discovers a strange energy signal that leads them to the wizarding world. Harry Potter and his friends are initially suspicious of these strange newcomers. But then they realize they can work together. The Enterprise could offer some of their advanced technology to help Hogwarts protect itself from dark wizards, like using their sensors to detect hidden dark magic.
One possible plot could be that the Hogwarts students are on a field trip when they accidentally stumble into the world of the Enterprise. Harry and his friends could help the Enterprise crew deal with a magical threat that the crew's technology can't handle. For example, a dark wizard has created a spell that is causing chaos on the Enterprise and only magic can reverse it.
One possible plot could be that Gaster somehow gets transported to the wizarding world of Harry Potter. He might initially be confused but then start to study the magic there. Maybe he tries to combine his own knowledge with magic, leading to some unique spells or potions. Harry and his friends could be both intrigued and cautious of this strange new character.
One possible interesting plot could be that the magic from the Harry Potter world starts to seep into the Percy Jackson universe, causing chaos among the demigods. For example, Hogwarts could suddenly appear in the middle of Camp Half - Blood. The demigods, not used to this type of magic, would be both curious and threatened. Meanwhile, Harry and his friends could get accidentally transported to the Percy Jackson world and have to team up with the demigods to figure out how to send Hogwarts back and restore the balance between the two magical systems.
Hermione Granger and Spock would be really interesting. Hermione is known for her intelligence and knowledge. Spock is also highly intelligent and logical. They could have some really in - depth discussions about the differences between magic and science. Hermione could try to explain the principles of magic to Spock, and Spock could attempt to make Hermione understand the Vulcan way of thinking and the science behind the Enterprise's technology.
One idea could be exploring the business side of the wizarding world in more detail. For example, how do they manage the supply and demand of potions ingredients? Another could be a fanfic about starting a new magical enterprise, like a flying broomstick rental service for tourists visiting Hogwarts. Maybe also a story about an entrepreneur trying to revolutionize the wizarding fashion industry with new robes made from enchanted fabrics.
Perhaps Harry is on a trip outside of the wizarding world when he comes across Venom. At first, they are at odds as Venom views Harry as a potential threat. But as they get to know each other, they find out that they both have a sense of justice. Venom is impressed by Harry's magical abilities and Harry is intrigued by Venom's strength. They then team up to take on a common enemy, like a powerful sorcerer who is using dark magic to create chaos in both the Muggle and wizarding worlds.
Well, it could be that Harry Potter, while on a magical mission, somehow gets transported to Star City where Oliver Queen operates. Oliver, being the vigilant Arrow, at first mistakes Harry for a threat. But then they realize they both fight for justice in their own ways. Harry could use his magic to assist Oliver in taking down some really tough villains that the Arrow alone couldn't handle, like some dark magic - infused criminals.
One possible plot could be that Harry Potter is somehow transported to the time of King Arthur through a magical mishap. Maybe he has to use his wizarding skills to help King Arthur in a battle against dark magic that is threatening Camelot. His spells and knowledge of magic could be a great asset.
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.