Maybe a plot where Superman and Power Girl have to deal with a misunderstanding in the public's perception of them. This leads to them having to work together to clear their names and also protect the city at the same time. They start to understand each other better during this process.
One interesting plot could be a team - up between Power Girl and Superman against a powerful new villain from another dimension. They have to combine their super - strength and other abilities to stop this threat that is causing chaos across multiple universes.
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.
In some 'evil superman x reader fanfiction', there could be a plot where the reader is the only one who can see the good that still exists deep within the evil Superman. The reader tries to bring out that good, leading to a series of intense and emotional interactions between them. It's like a battle between the evil side of Superman and the potential for redemption that the reader believes in.
In a Harley Quinn x Superman fanfiction, there could be a plot where Harley Quinn is hired by someone to assassinate Superman. But as she gets to know him during her attempts, she realizes he's not what she thought. So instead, she decides to protect him. This change of heart could create a lot of drama and action as they face off against the forces that hired her in the first place. Also, it could explore how their different personalities - Harley's wildness and Superman's moral righteousness - interact and complement each other.
Some fanfictions focus on the relationship between Superman and Power Girl outside of their superhero duties. For example, they could be attending a family gathering where they have to deal with all the normal family drama, but with the added complication of being super - powered. There are also stories where they train together, sharing their different combat techniques and learning from each other. This not only helps them become better heroes but also deepens their bond as family members in the DC lore.
Darkseid can also be a common antagonist. His goal of universal domination means that he would see Superman and Power Girl as threats to his plans, and he would send his minions or come himself to fight them.
In some fanfictions, they might explore different universes together. Goku is used to traveling between different realms, and Power Girl could be intrigued by the new places. They could have adventures and learn from each other's cultures and powers.
In some naruto x girl kyuubi fanfiction, the plot might revolve around the girl being an outcast because of her Kyuubi - like powers. Naruto, who has always been an outcast himself, helps her accept herself. They then train together to master their powers and become a formidable duo in the ninja world. This could also lead to a romantic relationship as they understand each other on a very deep level.
One interesting plot could be Superman traveling back in time to prevent the destruction of Krypton. He could use his powers to stop the cataclysmic events that led to its downfall. Maybe he tries to convince the Kryptonian council of the impending danger, but faces resistance as they don't believe him at first.
One interesting plot could be that they team up to fight a new and extremely powerful villain from another dimension. This villain has powers that neither Superman nor Supergirl has faced before, forcing them to combine their unique abilities in creative ways.