Time-active

A time-active civilisation or power was one which has mastered time travel and its paradoxes. These were apparently not common in the universe, in no small part due to the intervention of the Time Lords, who did not look kindly upon potential rivals. (TV: The Time Warrior, The Two Doctors, PROSE: Sky Pirates!)

Examples of time-active
The Gallifreyan civilisation - in particular, the Time Lords - were one of the most significant temporal powers.

The Faction Paradox, a time active organisation which revelled in paradox. They could also be seen in some fashions as a temporal terrorist organisation. (PROSE: Alien Bodies)

The Daleks had time travel technology. (TV: The Chase and others) Surviving Daleks retained the ability to manage "emergency temporal shifts". (TV: Doomsday, Evolution of the Daleks)

The Monan Host, while not on par with the Time Lords, possessed powerful timeships. (AUDIO: The Apocalypse Element)

The Enemy were another power opposed to the Time Lords. (PROSE: Alien Bodies)

The Time Agency were an organisation of 51st century individuals (likely humans) who developed a vortex manipulator to master time/space travel. (TV: Utopia, The Sound of Drums) The organisation later disbanded. (TV: Kiss Kiss, Bang Bang)

The Trods developed time travel technology. (COMIC: Pursued by the Trods)

The Cybermen used time travel on several occasions in an attempt to conquer more vulnerable time periods. (TV: Attack of the Cybermen, AUDIO: Real Time, COMIC: The Flood)

The Androzani trees were capable of forming a psychically controlled room capable of safely navigating the Time Vortex. (TV: The Doctor, the Widow and the Wardrobe)

A group of Slitheen managed to create temporal drives for use in a time travel tourist package. (PROSE: The Slitheen Excursion)

The Korven had ambitions to rule time and space and attempted this by invading in the past planets they had failed to conquer in their own time. (TV: The Korven, The Eclipse of the Korven)

The Nekkistani used time-cruisers to travel the Time Vortex. (AUDIO: Terror Firma)

The Order of the Black Sun started the first time war against the Time Lords. (COMIC: Star Death, 4-D War, Black Sun Rising)