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