Pre-universe

The Pre-Universe was the Universe which came before this one. After the destruction of the Pre-Universe, some species found their way into this Universe, and some (such as the Old Ones) ended up with god-like powers. (NA: All-Consuming Fire, MA: Millennial Rites)

It had a green void, stars shaped like doughnuts and physical laws closer to what might be understood as magic. (MA: Millennial Rites)

Knowledge of this universe was a closely guarded secret, and was only in the Doctor's possession as a result of his connection to the Matrix during his time as Lord President. (MA: Millennial Rites, DW: The Invasion of Time) Even then, the knowledge would ultimately prove temporary; In his Sixth and seventh life, the Doctor was fully conversant with the details and specifics of this universe (NA: All-Consuming Fire, PDA: Synthespians™), whereas by his tenth it would almost be an article of religious faith to him that such a universe could not have existed. (DW: The Impossible Planet)

The Beast claimed to have originated before the universe, and to have been imprisoned by the Disciples of the Light, likely placing both in the Pre-Universe. (DW: The Impossible Planet / The Satan Pit)

Though in point of fact the Beast claimed to have been imprisoned "Before Time," and debatably the Pre-Universe could still be a part of "time".

Abaddon, being the son of the Beast, probably also came from this period and was imprisoned around this time. (TW: End of Days)

The Ancient Lights were speculated by Luke Smith to have come from the Pre-Universe. (SJA: Secrets of the Stars)