Unnamed Borg tactical cubes

This article lists Borg tactical cubes without any known designations.

Grid 986 tactical cube
At least one tactical cube was present in a nebula within Grid 986 of the Delta Quadrant in 2377 where the USS Voyager discovered one the Borg's transwarp hubs. This vessel was one of several Borg ships to attack the Voyager as she made her second intrusion into the nebula to try and get home to Earth using the hub. 
 * The tactical cube did not actually appear in the episode but was present in an image representing the events in the 2005 Ships of the Line calendar.

T'Uerell's tactical cube
This tactical cube was brought from the Delta Quadrant through a transwarp conduit by T'Uerell into a nebula to aid her Borg forces against a combined Starfleet/Klingon/Romulan fleet. Having encountered a tactical cube before, Admiral Kathryn Janeway of the USS Voyager explained to Captain Jean-Luc Picard of the USS Enterprise (NCC-1701-E) what to expect. It gave the fleet a beating, but was eventually destroyed.