Here is the full list of all 35 Age of Civilizations II achievements.
Create 50 vassals
Join 50 alliances
Form Japan
Form Austrian Empire
Form Italy
Create 20 vassals
Form Australia-Hungary
Create 50 unions
Form Russian Empire
Capture 1500 provinces
Form Ottoman Empire
Create 25 unions
Create 10 unions
Create 5 unions
Create 5 vassals
Adopt the ideology of Communism
Adopt the ideology of the City State
Adopt the Horde ideology
Adopt Republic ideology
Adopt the ideology of democracy
Join 25 alliances
Capture 750 provinces
Adopt the Monarchy government
Adopt Fascism ideology
Capture 500 provinces
Create union
Create a vassal
Capture 300 provinces
Capture 150 provinces
Join 10 alliances
Capture 75 provinces
Join 5 alliances
Join alliance
Capture 30 provinces
Capture 10 provinces