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