Ascension of the Cybermen
click on images to enlarge
Cyberdrones were disembodied Cyber-heads which served as an advance guard for the Cybermen during the Cyber-Wars.
Capable of flight, Cyberdrones appeared as disembodied Cyber-helmets corresponding with the Cybermen design associated with the Cyber Legions in N-Space, who themselves were all but identical to those created by John Lumic and Cybus Industries in Pete’s World. Their eye-pods, which gave a blue glow of light, served as both a means of vision, providing a heads-up-display to pinpoint targets, and an energy weapon, firing blue pulses. (Ascension of the Cybermen)
In the immediate aftermath of the Cyber-Wars, the Lone Cyberman and his Cyberguards used a flight of Cyberdrones to attack the Thirteenth Doctor and the last surviving humans. (Ascension of the Cybermen)
In one parallel universe, a Cyber-Controller used “Cyberdrone” as a term for the fully-converted Cyberman units subordinate to it. (Code Silver) Similarily, a Borg-modified Cyber-Controller who crossed from N-Space to the Federation universe refered to its subordinates as “drones”. (Assimilation²)