Maybe Jaden gets hit by a strange ray from an experiment gone wrong. As a girl, he starts to notice how people treat him differently. He could use this experience to understand the female perspective better. For example, he might join the girls' sports team and learn about the discrimination they sometimes face in sports. He then tries to make a change in the school's attitude towards girls' sports.
In a 'Jaden turns into a girl' fanfiction, it could start with Jaden waking up one day as a girl. He is really confused and a bit scared at first. But then he realizes that this could be an opportunity. He decides to enter a beauty pageant that his school is having, not to win but to prove that girls should be judged by more than just their looks. Along the way, he makes new friends among the girls and also helps his male friends understand the importance of inner beauty.
Perhaps a jealous classmate. This classmate was always in the spotlight before Jaden turned into a girl. But now, with Jaden getting all the attention because of this strange transformation, the classmate feels left out and decides to be the antagonist. They might try to sabotage Jaden's new friendships or chances to participate in school activities.
Well, in a Todoroki turns into a girl fanfiction, perhaps there's a villain who has a transformation quirk and uses it on Todoroki as a form of psychological warfare. Todoroki, now a girl, has to find a way to reverse the effect. In the process, he/she realizes that society treats female heroes differently and has to fight against those prejudices too. Maybe he/she even uses this new form to her advantage in some battles, by using the element of surprise.
One possible plot could be that Cloud, after turning into a girl, has to adapt to a world that now views her differently. Maybe she struggles with newfound emotions and social expectations. For example, she might have been a tough warrior as a male, but as a girl, people underestimate her. She then has to prove herself all over again in battles or quests, while also dealing with her own internal confusion about her new identity.
Well, perhaps the story could start with Keith being exposed to a strange energy. This energy alters his DNA, turning him into a girl. As a girl, he finds that he's now treated differently in society. He uses this experience to understand the struggles that girls face. He might also have to adapt to physical changes like different body strength and new ways of expressing emotions.
Perhaps there's a powerful artifact that Gohan touches, and it transforms him into a girl as a form of curse. In this new form, Gohan starts to notice different things about himself and the world around him. He might have to learn new ways to fight and move, as his body is now different. His relationships with his friends like Videl and Piccolo could also change, as they try to help him adapt and find a way to break the curse.
Well, perhaps the plot could involve Minato suddenly waking up as a girl and having to navigate a world that now sees him in a different light. He might struggle with new social expectations and how his friends and family react to this change.
Well, it could start with Marco waking up one day as a girl. At first, he's completely bewildered. He might try to hide it from his family and friends at first. But as time goes on, he starts to adapt. Maybe he even joins a new group of friends who are all girls and they introduce him to new hobbies and interests. The story could also deal with how he feels about his male friends now that he's a girl. He might have different dynamics with them, and some might even develop romantic feelings for him, which adds a whole new layer of complexity to the story.
Maybe the plot could involve Saitama, now as a girl, trying to figure out how to reverse the transformation. Along the way, she discovers new aspects of her personality. She might become more empathetic as a girl and use this new trait to better understand the civilians she protects. She could also have some comical encounters with other heroes who are very confused by her new appearance.
In a 'luigi turns into a girl' fanfiction, the plot might involve Luigi being transformed due to a strange experiment gone wrong in the Mushroom Kingdom's science lab. His new female form causes a stir among the inhabitants. He could struggle with how others perceive him now. For example, some characters might treat him differently. However, he also uses this opportunity to see the world from a different perspective and becomes more confident in himself over time.
One possible plot could be Dipper's struggle with his new identity. He might have to deal with how his friends and family react. For example, Mabel could be super excited to have a sister for a change. And Dipper would have to navigate a world that treats him differently as a girl, like different expectations in Gravity Falls' strange society.