Planet 14

Planet 14 was a planet where the Second Doctor had an encounter with the Cyber-Director. Both survived this encounter.

Doctor Who: Cybermen, a book written by David Banks suggests that Planet 14 is located within the Sol System and that a subspecies of early Cybermen from Mondas migrated to Planet 14 following a divergence from the 'Mondasian' Cybermen, eventually evolving into The Invasion-era Cybermen. However this has not been accepted within the wider continuity as Canon

The World Shapers, a DWM comic strip suggests that Marinus is the planet that the Cyber-Planner from The Invasion refers to as Planet 14. This also has not been confirmed as Canon