Omniverse

The Omniverse or the All was the totality of all of existence, every individual multiverse. Although in this terminology "a multiverse" was a smaller grouping of universes within this totality, (COMIC: The Glorious Dead) the phrase "the Multiverse" was also often used to mean the totality of parallel realities, rather than a particular grouping of them. (AUDIO: Palindrome, Restoration of the Daleks, et al.) The term "all creation" was also used to refer to the totality of existence. (TV: Journey's End, WC: )

Structure
The Time Vortex of the Doctor's own multiverse merged with the omniversal spectrum at the Glory, a device at the spectrum's focal point that maintained the structure of the omniverse as long as there was a living consciousness to direct it. (COMIC: The Glorious Dead)

The omniverse consisted of infinite dimensions, and Lampreys were capable of devouring entire multiverses within the omniverse. (PROSE: Spiral Scratch) The Sixth Doctor explained that while travelling the omniverse, time was relative and so "urgency" and "lateness" were non-existent where time travel was concerned. (AUDIO: Paper Cuts)

The Seventh Doctor called the Silurian Earth reality an unnatural branching of the omniverse, artificially created as opposed to Arthur's World which was natural. The Guardians of Time were one of the powers of the omniverse who could do anything, bound only by laws of conduct. (PROSE: No Future)

History
During the Last Great Time War between the Dalek Empire and the Time Lords, Lord President Eternal Rassilon grew so desperate to survive he devised the "Ultimate Sanction," which called for all of "creation" to crumble behind the Time Lords as they ascended to be beings of pure consciousness that no longer relied on linear time. (TV: The End of Time) Upon learning of this plan, (PROSE: The Whoniverse) believing that his people had become just as vile as the Daleks, the War Doctor stole the Moment superweapon from the Omega Arsenal for use against both sides, hoping to end the Time War once and for all by destroying Daleks and Time Lords alike (PROSE: The Day of the Doctor) before their conflict destroyed everything else. In the post-War universe, the Tenth Doctor and prevented Rassilon from bringing forth his plan by throwing the Time Lords back into the War. (TV: The End of Time)

In 2009, Davros and the New Dalek Empire took 27 planets, including the Earth, from their spaces in N-Space and placed them in the Medusa Cascade. They plotted to use the planets as a vast transmitter for their reality bomb, which would totally destroy every atom in the universe. However, the bomb's wavelength would also break through the rift at the heart of the cascade, meaning it would spread to every universe. As Davros and the Supreme Dalek explained, the bomb would destroy all of existence itself, leaving the Daleks the sole life forms in all of reality. Their plan was ultimately stopped by the efforts of the Tenth Doctor, his Meta-Crisis self, and the Children of Time. (TV: Journey's End)