Iconian

The Iconians were an ancient and advanced civilization that ruled a small empire from their homeworld, Iconia, in the Beta Quadrant. From Iconia they used gateways to travel to countless worlds across the galaxy, earning them the nicknames "Demons of Air and Darkness". Around 200,000 years ago the Iconians were supposedly wiped out following an orbital bombardment of Iconia. (TNG episode: "Contagion", and novel: Gateways #3: Doors Into Chaos).

The Iconians also possessed territory in the Gamma Quadrant, such as Vandros IV and its surrounding territory. (DS9 episode: "To the Death")