In Dr Who, the Cybermen originally came from Mondas (in The Tenth Planet) but later settled on the planet Telos. They have attempted to conquer and enslave Earth in many episodes. In the 2006 season of the show, they were seen evolving on a parallel Earth.
Off-screen, they were created by Script editor Gerry Davis and scientist Kit Pedler.
Source from which the Borg were shamelessly ripped in Star Trek.