In a fanfiction of this kind, we might see the Hogwarts houses incorporated into Star Trek. The Sorting Hat could be brought into the Star Trek universe and sort the crew members. Spock might be a Ravenclaw for his intelligence, while Kirk could be a Gryffindor. Also, the idea of the Deathly Hallows in the Star Trek world is fascinating. The Elder Wand could be a powerful weapon against the Klingons or other enemies.
Some fanfictions might explore the concept of immortality in both universes. In Harry Potter, there are ways to achieve immortality like the Philosopher's Stone. In Star Trek, there are species with long lifespans. Combining these ideas, a story could be about Harry, who is immortal, traveling through the Star Trek universe and sharing his knowledge of immortality with the long - lived species there.
One interesting crossover could be the use of magic in the Star Trek universe. For example, a fanfiction might have a wizard or witch from Harry Potter end up on the Enterprise and use magic to solve some of the ship's problems, like a strange alien energy field that normal technology can't deal with.
There might be crossovers where the characters interact. Picture Captain Kirk meeting Harry Potter. Kirk could introduce the concept of exploring new galaxies to Harry, while Harry could show Kirk some magic spells. In fanfiction, this could lead to all sorts of adventures, like the two of them teaming up to fight a common enemy that threatens both the Federation and the wizarding world.
One interesting crossover could be the use of magic in the Star Wars universe. For example, a Harry Potter character might introduce spells to the Jedi or Sith. It could add a new dimension to lightsaber battles, like using a spell to disrupt the energy of a lightsaber. Another aspect could be the cultural exchange. The Hogwarts houses could be compared to the different factions in Star Wars. Gryffindors might be seen as similar to the Rebel Alliance, with their courage and sense of justice. Slytherins could have parallels to the Sith in terms of their ambition and cunning.
One interesting crossover could be the use of magic from Harry Potter in the battles of the Avengers. For example, Hermione's intelligence and knowledge of spells could help the Avengers come up with new strategies. Another aspect could be the idea of an immortal character from the Potterverse interacting with the Avengers. Maybe a powerful wizard or witch becomes an ally of the Avengers and uses their magic to enhance the team's capabilities.
One interesting aspect could be the magic of Harry Potter combined with the superpowers in Marvel. For example, imagine Harry using his Patronus charm while fighting alongside Iron Man. The Patronus could act as a distraction or even a form of defense against some of the villains in the Marvel universe.
There could be a fanfiction where the characters from both universes meet at a sort of interdimensional crossroads. For example, Hermione could team up with Spock. Hermione's vast knowledge and logical thinking, combined with Spock's Vulcan logic, could make for an interesting duo as they try to find a way back to their respective universes while also facing various challenges along the way.
One interesting crossover could be Kim Possible characters getting involved in a Star Trek mission. For example, Kim could use her martial arts skills to help the Star Trek crew in a physical confrontation on an alien planet. Maybe Ron Stoppable's clumsiness could lead to some comical yet ultimately helpful situations, like accidentally activating a crucial device on the Star Trek ship.
A common crossover is the appearance of Starfleet officers in the Warhammer 40k universe. They might be seen as strange and otherworldly beings. Their peaceful exploration ethos would be a sharp contrast to the constant warfare in 40k. For example, they could try to broker peace between warring factions in 40k, which would be a huge challenge given the nature of that universe.
One interesting crossover could be the sharing of technology. For example, the warp drive from Star Trek might be compared or combined with the hyperspace technology in Babylon 5. Another aspect could be the meeting of different alien species from both universes. Maybe the Vulcans from Star Trek and the Minbari from Babylon 5 could engage in some sort of philosophical exchange.
Well, in some fanfictions, you might see the Death Star being infiltrated by Hogwarts students using their magic skills. They could use invisibility cloaks to move around undetected and use spells to disable the security systems. Also, the idea of a lightsaber duel between a Star Wars character and a Harry Potter character who uses a magically enhanced sword could be really cool. It would be a clash of two very different but equally powerful combat styles.