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