Dalek Battlecruisers were a large part of the Dalek Empire's fleet.
History
Hundreds of battlecruisers faced Movellan Battlecruisers during the Daleks' war with the Movellans due to a stalemate that had been reached. (TV: Destiny of the Daleks)
When Davros, the creator of the Daleks, was being held aboard a prison space station, the Daleks used one of their battlecruisers to attack the station and retrieve him. (TV: Resurrection of the Daleks) This was a "supercharged class 6" battlecruiser, equipped with Grade-A Terror Weapons and treble reinforced shields. It was known in to the militaries of other species as the "Ball Crusher." (PROSE: Resurrection of the Daleks)
Battlecruisers were among the Dalek fleet that fought in the Last Great Time War. The Time Lords planned to unleash a genetically engineered breed of Dalekanium-eating Vashta Nerada against them but were forced to abandon the project following an incident on Synthesis Station. (AUDIO: Day of the Vashta Nerada)
Some Dalek saucers were also classed as battle cruisers; the Eleventh Doctor initially took Ship Sigma to be a battle cruiser before learning it was a survey ship. (COMIC: The Dalek Project)