I'm not really into the idea of creating Powerpuff Girls OC, since someone has to create them using either Sugar, Spice and Everything Nice, or Snips, Snails and a Puppy Dog's Tail, with an addition of Chemical X. It makes the Powerpuff Girls and the Rowdyruff Boys feel less special.
If I'm designing PPG OCs, I prefer making them look like the side characters from the original series, with dynamic looks and such. alongside Townsville villains for the PPG to face.
Mhm.. I always wanted to see an amazing rowdyrufff boys OC, but never did. I wanted them to be real bad looking and cool, like... The rowdyruff boys. I want one of them to beat up bubbles by flirting with her.