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