For civs that debuted in Civilization I through IVnote America, Arabia, the Aztecs, Babylon, Byzantium, Carthage, the Celts, China, Egypt, England, Ethiopia, France, Germany, Greece, the Hittites, the Holy Roman Empire, the Inca, India, the Iroquois, Japan, the Khmer, Korea, Mali, the Maya, Mongolia, the Netherlands, the Ottomans, Persia, Portugal, Rome, Russia, the Sioux, Spain, Sumer, the Vikings, the Zulu see here.
For civs and cross-civ leaders that debuted in Civilization V through VInote Assyria, Australia, Austria, Brazil, Canada, the Cree, Denmark, Eleanor of Aquitaine, Gaul, Georgia, Gran Colombia, Hungary, the Huns, Indonesia, Kongo, Kublai Khan, Macedon, the Maori, the Mapuche, Morocco, Norway, Nubia, Phoenicia, Poland, Polynesia, Scotland, Scythia, the Shoshone, Siam, the Songhai, Sweden, Venice, Vietnam, see here.
For civs and leaders in Civilization VII, see here.
