Cybertron

A Cybertron was a villain in Professor X. Dave Young played the part of a Cybertron in one of the final episodes of the series in the late 1980s. (PROSE: Escape Velocity)

Behind the scenes
With Professor X serving as equivalent to Doctor Who within the Doctor Who universe, the Cybertrons are a clear analogue to the Cybermen. Alternatively, the Cybs were mentioned in Synthespians™.