There was once an alliance that was built over many millennia, of four great races of the galaxy: the Asgard, the Nox, the Furlings, and the Ancients. Writings left behind at places such as Heliopolis have revealed information about the lost Furling race. The discovery of a stone key in a pharaoh's tomb in Egypt led to a temple found on P5X-777 that was of Furling design, intended as a doorway to a utopian Paradise.
Although SG-1 has not yet encountered the Furlings, they have allowed their imaginations to conjure the unlikely image of small, furry, benevolent Ewok-like creatures.
Cross Reference: Ancient Alliance, Fifth Race, P5X-777, Paradise
Episode Reference: The Fifth Race, Paradise Lost, 200