They appeared in the episode Hot Tub where the Drawn Together gang was watching them fight each other to the death in a fighting arena.
They appeared again at the beginning of Freaks & Greeks where they were seen screaming and running around in terror while Wooldoor killed them all with a lawnmower.
The Smurfs were seen in The Drawn Together Movie: The Movie! where they were all at Papa Smurf's funeral. Smurphette spat on his grave and yelled at him "I hope you Smurf in Hell for what you did!" They all discussed how horrible of a person he was for doing whatever it is that he did before they were all crushed by the passing by carriage.