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