Queen Laura from Outlaw . She just looks like she’s tickled to death most of the time, wearing those ridiculous outfits and hamming it up with Jack Palance.
Can’t forget Oppenheimer aka Professor Patent Papers from Riding With Death either. Just because it’s the next best thing to literally seeing an MTM supporting character as a villain on a TV “drama.” 
(As the riffers are happy to tell us. He was the voice of Skeletor for many years, too. For you He-Man fans.)