Seven of Nine's cube
This Borg cube, which hosted Seven of Nine, assisted  in developing the bio-molecular warhead against Species 8472 in 2374. 

When Voyager approached the vessel, it was locked in a tractor beam and Captain Kathryn Janeway was beamed aboard to negotiate the development of the warhead. After Species 8472 destroyed a nearby planet, the cube tractored Voyager to warp and to safety to develop the weapon. Janeway and Tuvok, with Seven of Nine as a representative, worked in the vessel on the weapon until the cube was attacked by a Species 8472 bio-ship. The Borg knew that they could not allow Voyager to be destroyed; and so the cube rammed the bio-ship, destroying both. Portions of the cube were beamed into one of Voyagers cargo bays along with Tuvok, Janeway, Seven of Nine, and a number of Borg. ()

A visual of this cube firing on a Species 8472 bio-ship was later used to show the drone One information about the Borg in 2375. ()
Unnamed Borg starships