A fake custom-designed H-B logo for Bewitched.
Speculation once rose that Hanna-Barbera was planning an animated spinoff series of the classic 1960's TV sitcom, Bewitched (much like what they did with Jeannie in 1973). It was hinted by the fact that H-B animated the opening intro, one episode of their classic series, The Flintstones featured a crossover with the characters from both sitcoms, and that Bewitched was produced by Columbia Pictures' television subsidiary at the time, Screen Gems, in which at that point produced Hanna-Barbera cartoons under an agreement made. It was rumored that an unreleased pilot of the cartoon had been made circa 1967 but never broadcasted. However, this rumor soon got debunked, and that no such production for a Bewitched cartoon has ever been made. Further speculation revealed that H-B's deal with Screen Gems expired around that same time, so it would have been unlikely for something to have been planned this late into their closing deal (though some people think that this may have what caused the "missing pilot" to have been cancelled).