One idea could be a body - switching with a regular person who then has to deal with Power Girl's powers and responsibilities. They might struggle to control her super strength and flight, leading to some comical situations in the city. For example, accidentally crashing into buildings while trying to fly. Another plot could involve a villain who switches bodies with Power Girl to gain access to her powers and use them for evil. Then, Power Girl has to figure out how to get her body back while trapped in the villain's weaker form.
A possible plot is that Power Girl switches bodies with another superhero. This could lead to a exploration of how different heroes approach the use of their powers. Maybe they have different moral compasses when it comes to using Power Girl's abilities. For instance, one hero might be more aggressive in using her strength in combat, while Power Girl is more cautious. It could also create a situation where they have to learn about each other's personal lives and secrets while in the wrong bodies.
If a villain switches bodies with Power Girl, they would likely immediately try to use her powers for evil deeds. They might go on a rampage, using her super strength to cause destruction. Power Girl, on the other hand, in the villain's body would have to be very strategic. She would need to use her knowledge of the villain's lair and minions to her advantage, while also trying to convince the other heroes that she is not who she appears to be. And for an ordinary person who switches with Power Girl, they might be overwhelmed at first, but then start to adapt and even have some fun with the powers, like flying around the city to see the sights.
A possible plot could be that they are given a time limit to switch back. During this time, they have to keep their situation a secret. The boy in the girl's body has to deal with her family, like having to pretend to be interested in things like fashion shows on TV which he normally wouldn't. And the girl in the boy's body has to participate in sports activities that the boy is part of, which is a whole new experience for her.
One plot idea could be that Spiderman and Power Girl team up to stop a powerful villain who is causing chaos in both their cities. They start off not getting along due to their different methods but gradually learn to respect each other.
A plot could involve Power Girl coming from an alternate universe and Superman having to help her adjust to his world while they also discover a connection between their two universes that could be dangerous if not fixed. This would explore their relationship as cousins and how they deal with the differences in their upbringings.
A great plot idea is the character learning about the other gender's emotional world. The boy in the girl's body might realize that girls often suppress their feelings due to social norms. He could then try to break those norms and express emotions more freely. Or perhaps there's a mystery element. The body swap could be part of a larger plan by some unknown force, and the character has to figure out why it happened and how to reverse it while dealing with the challenges of living as the opposite gender.
A time - travel plot would also be cool. Power Girl could be sent back in time to a period when her powers were not fully developed. She would have to rely on her wits and the help of the people in that era to get back to her own time, all while trying not to change history too much.
A plot could revolve around a team-up that no one expected. Like a villain and a hero from different universes having to work together in the Tournament of Power. They start off distrusting each other but gradually learn to respect and rely on one another. This could add a whole new layer of drama and character development to the fanfiction.
One idea could be exploring the origin of the 'power of darkness'. Maybe it was a forgotten magic that gets rediscovered by a young protagonist.
A possible plot is that the body swap happens on a special day. The boy - turned - girl has to go on a date that the girl had planned. He tries to act as the girl but makes some funny mistakes. The girl - turned - boy has to participate in a sports event the boy was supposed to be in. They both start to see the world from a different perspective and learn to appreciate what the other gender goes through.
A fanfiction plot could be about a new threat that is specifically targeting the Omnitrix and the Power Rangers' power source. Ben and the Rangers have to figure out how the enemy is doing this and stop them. Along the way, they discover a hidden connection between the two power systems that was unknown before. There could be some character development for both Ben and the Rangers as they struggle to protect what they hold dear.