Transcendental being

Transcendental Beings are powerful beings who live outside the normal universe. Transcendental beings are made out of the very matter of time, with a polymorphic lattice of photinos and and chronons, bound together by super-strings. They have incredible powers, though they have difficulties interacting with normal life. Though they can reach the normal universe, they normally live in the Calabi-Yau Space and the Time Vortex. (DW: The Quantum Archangel)

The Guardians
The Guardians are the most important beings in the Calabi-Yau Space. The existence of the Guardians was known only to a few advanced species, among those were the Time Lords and the Eternals, who called them Enlighteners. Though they each personify different concepts, they are all part of the Six-Fold God. (DW: Enlightenment, The Quantum Archangel)
 * Black Guardian (Entropy)
 * White Guardian (Structure)
 * Red Guardian (Justice)
 * Azure Guardian (Equilibriam)
 * Crystal Guardian (Dream)
 * Gold Guardian (Life)

The Old Ones
The Old Ones are cruel and dangerous beings who attempt to conquer reality. They have a more active role in the normal universe.
 * The Gods of Ragnarok (DW: The Greatest Show in the Galaxy)
 * Nestene Consciousness (DW: Spearhead from Space, Terror of the Autons and Rose)
 * Nyarlathotep (DW: The Quantum Archangel)
 * Fenric (DW: The Curse of Fenric)
 * The Great Intelligence (DW: The Abominable Snowmen, The Web of Fear)
 * The Animus (DW: The Web Planet)

Their name reflects their supposed one-to-one relationship to certain of the "Old Ones" of H.P.Lovecraft's Cthulhu Mythos.

Other Types

 * Eternals (DW: Enlightenment)
 * Chronovores (DW: The Time Monster)
 * Time Wraiths (PDA: The Quantum Archangel)
 * Swimmers (PDA: The Quantum Archangel)

Possible Transcendental Beings
Some creature share some, but not all of traits of the transcendental beings.
 * Immortals (PDA: Deadly Reunion)
 * Reapers (DW: Father's Day)
 * Hunters (NA: The Pit)
 * Vortisaurs (BFA: Storm Warning)