The Run-of-the-Mill Girls are alternate versions of the Powerpuff Girls if they were created without the accidental usage of Chemical X, as seen in the episode "Oops, I Did It Again" when Professor Utonium realizes that all his greatest inventions have been accidents - including the girls. The Run-of-the-Mill Girls only appeared in the Professor's dream. In the episode, they have "dedicated their lives to just hanging around and doing nothing extraordinary."
- Bertha (Blossom) Leader of the 'Run-of-the-Mill Girls': she enjoys riding her bike, playing video games, painting nails, playing soccer, and getting good grades.
- Beatrice (Bubbles) Member of the 'Run-of-the-Mill Girls': she enjoys riding her bike, playing video games, doing her hair, playing volleyball and talking on the phone.
- Betty (Buttercup) Member of the 'Run-of-the-Mill Girls': she enjoys riding her bike, playing video games, getting pedicures and playing baseball. At one point, she attempts to kiss Mitch.
- Like most of the show's supporting characters, they have visible fingers, toes, eyebrows, ears, and noses.
- All of the girls have gotten in trouble with the Professor.
- Like average girls, they seem to keep a not-so tidy room.
- Unlike Bubbles and Buttercup, Beatrice and Betty are not strictly girly girl and tomboy; much like Bertha and Blossom, they both demonstrate traits associated with both of these personality types.
- The physical appearances of Bertha, Beatrice and Betty are based on redesigns that Craig McCracken briefly considered for Blossom, Bubbles and Buttercup in response to negative reactions from test audiences for the What A Cartoon! pilots.