Naruto and Sasuke are very commonly swapped. Their personalities are so different that it creates a lot of interesting scenarios. Naruto's optimism in Sasuke's body would be a huge contrast to Sasuke's usual brooding self. And Sasuke in Naruto's body would have to deal with Naruto's naivete and also his strong bonds with the other villagers.
Naruto and Kakashi are also fairly common. Kakashi's calm and collected nature is a far cry from Naruto's energetic self. If they swapped, Naruto would have to figure out how to use Kakashi's Sharingan and his more strategic combat style. Meanwhile, Kakashi would have to deal with Naruto's impulsive decisions and his unwavering determination.
Harry and Hermione are often swapped. Since Hermione is such a strong and capable character, it's interesting to see her in Harry's role. Also, Neville and Harry are commonly swapped as Neville also has the potential to be a hero.
The main characters are a mother and her daughter. Their names can vary depending on the specific version of the novel, but they are the two central figures whose body - swapping drives the whole story.
Adrien and Chat Noir could also be the main characters. Adrien is a model with a lot of public image to maintain, and Chat Noir is a flirty and carefree superhero. If they switched, there would be a lot of drama. Adrien might struggle with Chat Noir's more laid - back attitude towards his superhero identity, and Chat Noir would have to deal with Adrien's strict family life.
Naruto and Sasuke are the most common pair, no doubt. Their story arc in the official Naruto plot has so many layers that can be re - imagined in a slash relationship. But we also see pairings like Gaara and Naruto in some naruto slash fanfiction. Gaara's initially dark nature and Naruto's ability to reach out to him can be an interesting basis for a relationship in these stories.
One interesting concept could be the characters experiencing each other's daily lives. For example, Naruto might find himself in Sasuke's shoes, dealing with the Uchiha clan's legacy and his brooding nature. This can lead to a whole new understanding between the two characters. Another concept could be the change in fighting styles. If Sakura were to switch bodies with Kakashi, she'd have to quickly adapt to his Sharingan - enhanced combat skills.
The most unexpected pair to switch in 'Harry Potter Freaky Friday' fanfiction could be Neville and Bellatrix. Neville, who is kind - hearted and a bit clumsy at times, would suddenly be in the body of the cruel and powerful Bellatrix. Bellatrix, in Neville's body, would have to deal with Neville's insecurities and his new - found courage which would be a huge contrast to her normal self.
Definitely Naruto. His story is so central to the Naruto universe that it's natural for him to be a main character in black and white fanfiction. He has so many aspects to his personality that can be highlighted in this different setting. Sakura is also often featured. Her growth as a ninja and her relationships can be examined through the black and white lens. And then there's Itachi. His complex backstory and the choices he made can be re - evaluated in a black and white fanfiction, making him a very interesting character to write about.
The two central characters in the Freaky Friday full story are a mother and her daughter. The mother is likely an adult with a set of responsibilities such as running the household, may be having a job etc. The daughter is a typical teenager dealing with school, friends, and the normal growing - up stuff. Their lives are very different which is why the body - switching between them makes for such an interesting story.
Definitely Luke Skywalker and Leia. They are iconic characters, and gender - swapping them allows for a lot of creative exploration. But also, characters like Qui - Gon Jinn are getting more popular to be gender - swapped. His role as a mentor could be very different if he were a female. And Palpatine, too. A female Palpatine could be a very different kind of villain, with different motives and methods of achieving power in the Star Wars galaxy.
Definitely Marinette and Adrien. Since they are the main characters, when they are gender - swapped, it creates a whole new dynamic. People are really interested in seeing how a male Marinette would handle the Ladybug powers and responsibilities, and the same goes for a female Adrien as Chat Noir.