Borg cube

The Borg cube was the primary starship class of the Borg's fleet. They were part of the fleet of the Borg-Cybermen alliance along with Borg Spheres and Cyberships. (IDW: Assimilation²)

Behind the scenes
The Borg cube was the first and most common type of Borg ship to be seen in Star Trek, so much so that when the Borg appear, their cubes are rarely absent.