Ice Lord

Ice Lord was the higher caste of the Ice Warriors. (COMIC: Descendance)

While in a 23rd century museum on Deimos, Tamsin Drew pointed out an Ice Lord wearing traditional Ice Warrior burial regalia. (AUDIO: Deimos)

Isskar was once promoted to the rank of Ice Lord, and the Fifth Doctor detected this based on his appearance alone. (AUDIO: The Judgement of Isskar)

An Ice Lord was frozen and imprisoned on Shada. (PROSE: Doctor Who and the Krikkitmen)

Faction Paradox had agents among the Ice Lords of New Mars. It was them who alerted the Faction to the existence of I.M. Foreman's Travelling Show. (PROSE: Interference - Book Two)

Other references
In the video game Happy Deathday, played by Izzy Sinclair on the Time-Space Visualiser, an Ice Lord was among a host of "every single enemy" that the Doctor had ever defeated, who were assembled by the Beige Guardian and pitted against the Doctor's first eight incarnations. (COMIC: Happy Deathday)