The Originals

Katie didn’t have quite the right chemistry with Sheldon and Leonard, so the character was rewritten and recast with Kaley Cuoco in the role of the much more likable “Penny.”

It’s hard to imagine anyone other than Sally Struthers as Gloria Stivic, but here’s Kelly Jean Peters as Archie and Edith’s daughter in the original pilot for the then-titled sitcom, Justice for All before it became All in the Family.

We see the original Munsters’ lady of the house, Phoebe, played by Joan Marshall, looks like another then-popular horroresque housewife who was on another then-popular horror-themed sitcom.

The public defender in the pilot of the 1980s sitcom Night Court, was played by Gail Strickland, who wasn’t really memorable in her only episode, but she was the original.

Kit Smythe and Nancy McCarthy were Ginger and Bunny in the pilot. These characters were changed from two secretaries to a movie star and a small town girl, recast with Tina Louise and Dawn Wells, and the rest is history.

Three’s Company was one of the most popular US sitcoms of the mid-to-late 70s. Based on the British sitcom, Man About the House, it took some experimenting to create the winning formula that put the show at the top of the Nielsen’s.