You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own (AO3). They usually have a large collection of 'buttercup ppg fanfic' stories. Just use the search bar and type in 'buttercup ppg' and you'll get a bunch of results.
Self - discovery. Maybe through going against the rules, Buttercup discovers something new about herself, like hidden powers or different aspects of her personality.
The main characters are obviously Buttercup from the Powerpuff Girls and Butch from the Rowdyruff Boys. Buttercup is the tough and tomboyish one among the Powerpuff Girls, known for her strength and no - nonsense attitude. Butch, on the other hand, is one of the Rowdyruff Boys, who are usually the antagonists. He's rough and rowdy, but in this fanfic, he'll have a different side when it comes to Buttercup.
Well, it could be about Buttercup and Butch initially being rivals but then gradually realizing they have a deeper connection. Maybe they start off fighting over something silly like who gets to use a particular skate park. As time passes, they see each other's strengths and start to respect one another more. Eventually, this could lead to a friendship that might turn into something more romantic, like going on secret adventures together.
The fanfic might start with Buttercup feeling like she doesn't fit in with the Powerpuff Girls' image. She runs away to find a place where she can be herself more freely. Along the way, she might face challenges that make her grow as a character. For example, she could come across a group of outcasts who she initially thinks she can relate to, but then discovers they have different values. This could lead her on a journey of self - discovery and ultimately make her return to her sisters with a new perspective.
Well, there's a fanfic called 'Buttercup and the Mysterious Creature'. In this story, Buttercup stumbles upon a strange being and has to figure out what to do. It's full of action and shows Buttercup's determination. Also, 'Buttercup's Friendship Trials' is interesting as it focuses on her relationships with her sisters and friends within the Powerpuff Girls universe.
I'm not sure of specific 'buttercup against the rules ppg fanfic' titles off - hand. You could try searching on popular fanfic websites like Archive of Our Own. They usually have a large collection of Powerpuff Girls fanfics.
A lot of the fanfiction might have the theme of growth. As they interact, both Buttercup and Butch could grow as characters. For example, Buttercup might learn to be more patient with Butch's wild ways, and Butch could become more responsible because of Buttercup's influence. Another theme could be adventure. They might go on adventures together, facing challenges that test their relationship and their individual strengths.
I'm not sure about specific 'ppg buttercup x butch fanfiction' titles off the top of my head. But you can try searching on fanfiction websites like FanFiction.net or Archive of Our Own. There you might find some interesting stories about their relationship.