Robot Crawler
Whilst their Naval and power armoured counterparts gets to play around with their cool and snazzy CAT units, the Imperial Guard, feeling left out of the field, decided to one-up them by building a literal battlebot...okay maybe not on that levels, but it has a buzzsaw and that makes it cool.
Overview
These UGVs are called simply as Robot Crawlers, and they are a series of tracked Imperial Robots, that are used by the Astra Militarum. It is considered as a form of utilitarian UGV, akin to a miniature Centaur that can transform into various roles depending on what it has been equipped.
For example, it can turn into a mechanical mule by being equipped with literally nothing but an open basket to carry equipment around, become a reconnaissance unit by mounting a camera on top and using its small size to its advantage, or it can be armed with weapons, such as a buzzsaw arm to act as either a bomb-disposal unit or a breach-cutter unit.
Overall, the Robot Crawler is pretty god damned versatile, which is what the Guard needs anyway.