Cyberguards were Cybermen who were assigned to security duties.
History
During the 1986 invasion of Earth, the Mondasian Cyberguards stood within their Cybercraft. (PROSE: Doctor Who and the Tenth Planet)
In 2526, Neomorph Cyberguards accompanied the Cyber-Leader who invaded Briggs' freighter. (PROSE: Earthshock)
Neomorph Cyberguards were stationed on Telos. (PROSE: Attack of the Cybermen)
Two Cyberguards were with the Cyber-Leader in the the Alliance to stop the Eleventh Doctor from destroying the universe. (TV: The Pandorica Opens)
In the immediate aftermath of the Cyber-Wars, Ashad had two Cyberguards, who addressed him as Leader, to protect and help him fight on a refugee planet. (TV: Ascension of the Cybermen) They were killed when the Thirteenth Doctor, her companions and their friends destroyed Ashad's recovered Cybercarrier and the Cyber-Army onboard it. (TV: The Timeless Children)