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