Cylon reconnaissance drone
Reconnaissance Drones are vehicles of potentially similar size and purpose to the Colonial Raptor, but deployed by basestars.
The design of the craft probably has not changed greatly over time since the Cylon War, as a large number of them were easily identified by Lieutenant Kara "Starbuck" Thrace while reconnoitering the upper limits of the atmosphere of Ragnar while battlestar Galactica re-armed herself at Ragnar Anchorage (Mini-Series).
Similar vehicles were later seen by Boomer and Racetrack as they attempted to approach and destroy a basestar in orbit over Kobol (Kobol's Last Gleaming, Part II).
The precise capabilities of the drone are unknown. It is most likely not a fighter craft or a transport, as those roles are fulfilled by the Cylon Raider and Heavy Raider respectively.