For all intents & purposes, the season finale of She-Ra: Princess of Power in 1985 was "A Christmas Special". Of course, She-Ra's twin brother, He-Man, had top billing. His series was in reruns after production had ended a year earlier.
Man-at-Arms (Alan Oppenheimer) & Prince Adam (John Erwin) have finished a brand new transport vehicle intended for use against Skeletor (Oppenheimer). However, Orko (Lou Scheimer) has snuck aboard, and accidentally launches the Sky Spy. An attempt at landing the Sky Spy by magic takes Orko to Earth, and......!
It turns out She-Ra was renewed for a 2nd season, but became a weekly series because Filmation couldn't have 2 daily series at the same time anymore (Ghostbusters was launched in 1986). He-Man's adventures continued as he joined the cast of his sister's show. Unfortunately, when He-Man was relaunched a couple of years later, She-Ra wasn't included.