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