Friends had Joey. Happy Days had Laverne and Shirley. Every majorly successful sitcom, for better or for worse, produces at least one spinoff. Some never even make it to the air.
Karen
When Will and Grace went into its final season in 2005-06, plans were underway for the show to continue on with a spinoff featuring Megan Mullaly’s boozy, blunt Karen Walker character. Most of the action was to be based in her mansion, and have her yelling at her servants, including a butler, a part written for Martin Short. But after the Friends spinoff Joey played to lackluster ratings and critical apathy, the spinoff was called off.
Another Man’s Shoes
One Day at a Time wrapped up in 1984 after nine seasons, with the three main characters—a single mom and her two daughters—moving away from their Indianapolis apartment where they were constantly bothered by building superintendent Schneider. He was the breakout character (Pat Harrington, Jr. won an Emmy for the role), and CBS lined up a spinoff in which Schneider moves to Florida to care for his orphaned niece and nephew. The pilot ran immediately after the final episode of One Day at a Time, but it was never made into a full series.
Jackie Chiles
A year after Seinfeld ended, the show’s creators Jerry Seinfeld and Larry David met to write a show about Jackie Chiles, the sleazy lawyer portrayed by character actor Phil Morris and very obviously based on O.J. Simpson’s defense attorney Johnny Cochran. NBC was reportedly planning to air the show in early 2000, but Seinfeld and David never finished writing the script, and so a pilot was never made.
Horshack
In 1977, ABC planned to commit to just one of two spinoffs it had commissioned. The first was Fish, featuring Abe Vigoda’s character from Barney Miller interacting with his wife and five foster children. The other was about Horshack, the Welcome Back, Kotter “Sweathog” (Ron Palillo) who becomes a foster parent to his younger half-siblings. Horshack aired as an episode of its parent series, while Fish became the spinoff ABC greenlighted. (It lasted just over a year.)
The Mertzes
In 1957, I Love Lucy was ramping down after six years as one of the most popular shows on TV. Producer/co-star Desi Arnaz wanted to keep it going in some way and proposed a spinoff focused on the show’s neighbor characters, Fred and Ethel Mertz. William Frawley (Fred) immediately signed on, because it was a starring role. Vivian Vance (Ethel) immediately turned it down, because she absolutely hated working with Frawley and was very glad to move on. She even turned down a $50,000 bonus. With only one Mertz willing to do The Mertzes, the show never happened.