Games like Galactic Civilizations III: Retribution

If you finished Galactic Civilizations III: Retribution, the closest matches are Sid Meier's Civilization II, Age of Wonders: Planetfall, Warhammer 40,000: Gladius - Relics of War, StarDrive 2 and Lost Empire: Immortals. All 6 share its strategy genre and are ranked by how closely their themes and modes overlap.