Time dreadnoughts were Time Lord ships in a parallel universe where the Sixth Doctor led the Time Lords in War in Heaven. (PROSE: The Quantum Archangel) In the Doctor's main universe, the Time Lords also used large battleships with time travel capabilities during the Last Great Time War, such as Dreadnought Septima. (AUDIO: Hostiles)
During the alternative War in Heaven, they were armed with multiple time destructors, which were miniature Eyes of Harmony.
At least some of the dreadnaughts were named after important figures in Gallifrey or the planet itself, including the Glorious Aspect of Omega, Arcane Mystery of the Other, Blind Visage of Pythia, Righteous Fist of Rassilon and the Sacred Might of Gallifrey. (PROSE: The Quantum Archangel)