Multiverse

The Multiverse, also known as reality, (DW: Journey's End), and creation, (DW: The End of Time) was the place where all possible Universes resided, the empty spaces between the universes was known as the Void. (DW: Army of Ghosts)

The Clockworks were responsible for maintaining the basic structure of the multiverse. (EDA: The Blue Angel)

Iris Wildthyme's TARDIS could travel through the multiverse (BFIW: Wildthyme at Large) and the Axis was capable of allowing an individual to travel through the multiverse via portals that led to different timelines. (BFG: Reborn)

In the Medusa Cascade, Davros tried to destroy the multiverse using his Reality Bomb, but was stopped by the DoctorDonna. (DW: Journey's End)

In the final day of the Last Great Time War, Rassilon planned to destroy the whole of creation with the Ultimate Sanction. To escape the destruction of reality, the Time Lords shed their corporeal bodies and become creatures of consciousness alone, ones that would escape the effects of time and of cause and effect. This plot was foiled by the Doctor who used the Moment to destroy Gallifrey and cause the near-anhiliation of the Time Lords and the Daleks. (DW: The End of Time)

A Cyber-Leader at Stonehenge warned that with total event collapse, "all universes will be deleted", indicating that the phenomenon threatened the whole multiverse. (DW: The Pandorica Opens)