Luke Skywalker and Amuro Ray would make an interesting crossover. Luke's Jedi skills and Amuro's Gundam piloting abilities could lead to some great action scenes. They could learn from each other, like Luke teaching Amuro about the Force and Amuro showing Luke the ins and outs of Gundam technology.
I think Darth Vader and Dr. Doofenshmirtz would make an interesting crossover. Darth Vader's dark and menacing presence combined with Dr. Doofenshmirtz's comical evil - scientist shtick could lead to some really funny and unexpected interactions. Maybe Dr. Doofenshmirtz tries to steal Vader's lightsaber for one of his 'evil -inator' plans, and Vader is just completely confused by this strange little man.
Edward from Twilight could be a likely candidate. His brooding nature and special abilities might make for an interesting interaction with the Jedi or Sith in Star Wars. He could either be seen as a potential threat or an ally. Another would be Ahsoka Tano from Star Wars. Her strong will and combat skills could be interesting when pitted against the vampires of Twilight.
Definitely Harry Potter and Luke Skywalker. They both are heroes on a journey to defeat great evils. They could learn from each other's experiences and powers. Harry could show Luke some of the more subtle forms of magic, and Luke could teach Harry about the Force.
Han Solo and Commander Riker are also often crossed over. Han's roguish charm and piloting skills combined with Riker's military strategy and charisma make for an exciting pairing. They could be on a mission together, trading quips and sharing their different experiences from their respective universes. Another popular crossover is between Luke Skywalker and Spock. Luke's connection to the Force and his journey to become a Jedi, compared to Spock's logical Vulcan upbringing, offers a lot of room for character development and interesting interactions in fanfiction.
I think Kai would be really interesting. His hot - headed nature and his power over fire could make for some intense scenes in the Star Wars universe. He might be like a maverick Jedi or a Sith who doesn't quite follow the rules. He could get into battles with Stormtroopers using his fire powers in really creative ways.
Luke Skywalker and Marty McFly are often popular choices. Luke's heroism and Jedi powers combined with Marty's relatable and adventurous nature can make for great stories. Another popular combo is Darth Vader and Doc Brown. The contrast between the dark, powerful Sith Lord and the eccentric inventor can create a lot of drama and humor in a fanfiction.
Popular characters for crossovers include Goku. He's known for his amazing strength and transformations, which would be fascinating in the Star Wars world. Then there's Darth Maul. His double - bladed lightsaber and acrobatic fighting style could be an interesting match for the high - flying and fast - punching Dragon Ball Z characters. Also, Master Yoda. His wisdom and unique use of the Force could interact in an interesting way with the martial - arts - based combat of Dragon Ball Z characters.
Harley Quinn and Rey could be a popular crossover. Rey is a strong female character in Star Wars, and Harley Quinn has a very distinct personality. A fanfic could explore how Rey's determination and Harley Quinn's chaos - loving nature would interact, maybe they team up to take on a group of bad guys in a very unorthodox way.
Definitely Ragnar and Tyrion. Ragnar is a fierce and intelligent Viking leader, and Tyrion is a clever and witty character in Game of Thrones. Their interactions would be full of banter and strategic planning. They could both learn a lot from each other's ways of dealing with power and politics.
Another interesting pair could be Nick Wilde from Zootopia and Erin Reagan from Blue Bloods. Nick is a sly fox with a lot of street smarts, while Erin is a tough prosecutor. Their personalities would clash and also complement each other in an interesting way in a fanfiction. They could be involved in a case that spans both their worlds, with Nick using his charm and Erin using her legal knowledge to get to the bottom of things.