Shock troops

The Fourth Doctor identified Sontarans of the Sontaran Special Space Service who participated in the Sontaran invasion of Gallifrey as shock troops. (TV: The Invasion of Time)

According to the Dalek Survival Guide, the Daleks started using Ogrons as shock troops following the failure of the 2150s Dalek invasion of Earth; the guide suggested that the Ogrons' natural stupidity made them easier to control than humans and so eliminated the need for the time-consuming robotisation process. (PROSE: Dalek Survival Guide)

Gallifreyan shock troops served in the Last Great Time War. (AUDIO: The Rulers of the Universe) The Dalek Empire meanwhile harvested alternative versions of themselves, known through the conflict as the Skaro Degradations, to act as their shock troops. (PROSE: Engines of War)

As observed by the Eleventh Doctor in an alternate timeline, the cyber-converted Judoon served as the Cybermen's shock troopers, mindlessly destroying everything in their path. (COMIC: Assimilation²)