This is my list of 18 civilizations and their each 3 leaders:
1) USA (CivI-V)
-Washington (CivIV-V)
-F.D.Roosevelt (CivIV)
-Lincoln (CivI-IV)
2) Germany (CivI-V)
-Bismarck (CivIII-V)
-Frederick I Barbarossa (CivII). He increased the imperial authority in Germany, fought the Pope, and conquered territories in Italy.
-Hitler. He conquered one half of Europe. If you dont like him emotionally, my next option is Otto I (first German Emperor) because Frederick II the Great was King of Prussia, not of all Germany.
3) Rome (CivI-IV)
-Julius Caesar (CivI-IV)
-Augustus (CivIV)
-Justinian (CivIV). He was considered Roman Emperor by his people and his neighbours and conquered Northern Africa and Italy, so he recovered the city of Rome.
4) Greece (CivI-IV)
-Alexander the Great (CivI-IV)
-Pericles (CivIV)
-Milciades the Younger. He defeated the Persians in the battle of Marathon.
5) China (CivI-IV)
-Qin Shi Huang (CivIV)
-Mao (CivI-IV)
-Hongwu, also known as Zhu Yuanzhang. He expelled out the Mongols and was the first Emperor of Ming Dynasty.
6) India (CivI-IV)
-Ashoka (CivIV)
-Chandragupta II. During his rule, the Gupta Empire achieved its zenith politically and culturally.
-Nehru. He was the first Prime Minister of India and was the leader of the Indian National Congress under the mentorship of Gandhi, who never ruled in India.
7) Arabia (CivIII-IV)
-Harun ar-Rashid. He made the Abbasid Caliphate to achieve its zenith in culture, science, power and economy, and is famous to be in The Book of One Thousand and One Nights.
-Umar I. He conquered Mesopotamia, Siria, Persia, and Egypt and was the first Caliph to be called Amir al-Muminin (Prince of the Believers).
-Muawiyah I. He conquered lands in Anatolia, defeated Ali in the fitna, and was the first Umayyad Caliph.
(Saladin wasnt arab but kurdish and didnt rule in Arabia. Abu Bakr ruled only 3 years)
8) Spain (CivII-IV)
-Phillip II (CivII). In his time, Spain was the most powerful political entity in Europe and the most advanced land in science, tecnology and culture.
-Charles III. He applied politics of Enlightenment for the intelectual, educational and economic innovation of Spain, established Spanish symbols (flag and anthem) for the creation of an Spanish nation, and helped US in the War of Independence.
-Liuvigild. In the time of this Goth king, Hispania (Spain) was the most powerful economically, the most peaceful, and the most advanced intelectually in Western Europe.
(Isabel or Isabella was just Queen of Castille. However, his husband, Ferdinand, was King of Aragón and Castille and was considered King of Spain abroad.)
9) France (CivI-IV)
-Louis XIV (Civ II&IV)
-Napoleon (Civ I&IV)
-Charlemagne (CivIV). He was the King of the Franks, the old name of the French, so he fits in this civilization.
10) England (CivI-IV)
-Elizabeth I (CivI-IV)
-Victoria (CivIV)
-Henry II. He had huge territories in France and increased his authority against aristocracy and the Pope.
11) Russia-USSR (CivI-IV)
-Stalin (CivI&IV). If you dont like emotionally, my next option is Peter the Great.
-Catherine the Great (CivII-IV)
-Ivan IV the Terrible. He made Russia into an Empire conquering huge territories in Asia, established a new code of laws, and centralized the power.
12) Egypt (CivI-IV)
-Ramesses II (CivI,II&IV)
-Hatshepsut (CivIV)
-Akhenaten, also known as Amenhotep IV and Amenophis IV. He leaded a religious revolution changing the Egyptian politheism into monotheism (probably he made influence in the first jews), and concentrated the authority in himself.
13) Persia (CivII-IV)
-Cyrus the Great (CivIII-IV)
-Xerxes (CivII-III)
-Darius I (CivIV)
14) Babylon (CivI-IV)
-Hammurabi (CivI-IV)
-Nebuchadnezzar II. He built the Hanging Gardens, expelled out the Assyrians, and conquered Judah and Jerusalem.
-Nabopolassar. He left the Assyrian dependence and founded the Neo-Babylonian Empire.
15) Aztec Empire, also known as Mexica Empire (CivI-IV)
-Moctezuma II, also known as Moctezuma Xocoyotzin (CivI-IV). No more skulls in his hat, he isnt a cannibal.
-Moctezuma I, also known as Moctezuma Ilhuicamina or just Ilhuicamina. He subjugated the Huastecs, Totonacs and Mixtecs.
-Itzcoatl. He laid the foundations for the eventual Aztec Empire conquering the surrounding cities, and did a religious and law reform.
16) Incan Empire, also known as Tawantinsuyu (CivIII-IV)
-Pachacutec (CivIII)
-Huayna Capac (CivIV)
-Manco Capac. He founded the Kingdom of Cusco, the origin of the Incan Empire.
17) Ethiopia (CivIV)
-Zara Yaqob, also known as Constantine I (CivIV)
-Ezana. He was the first Christian ruler of the world, organized the Ethiopian Church, and destroyed the Kingdom of Kush.
-Haile Selassie. He fought Mussolinis armies and is considered the black reincarnation of Christ by the Rastafari (his pre-imperial name was Ras Tafari, that means Lord Tafari).
18) Japan (CivII-IV). Id choose Mongolia before, but the game developers will be interested in selling more games in Japan.
-Ieyasu Tokugawa (CivII-IV)
-Mutsuhito, also known as Meiji Tenno. He abolished the shogunate and the feudalism, leaded the Meiji Restoration to modernize Japan and to make it into an industrial country and a great power, and conquered Korea.
-Minamoto Yoritomo. He was the first Shogun of Japan and founded the Kamakura Shogunate, 1185-1333.