Who were the good guys in WW I?

(need to know all of them)

There were no "good guys" in the Great War. Every participating country had reasons to wage war, determining who was good and who was bad is practically impossible.

Basically the Austro-Hungarian Empire started the war, but it means nothing, since the war was inevitable.

If you mean that good guys = winners, then:

British Empire

French Republic

Russian Empire

United States

Italy

Japan

Serbia

Romania

Belgium

Brazil

Montenegro

Australia

Canada

Greece

India

Nepal

New Zealand

Portugal

South Africa

There may be a few other minor participants, but I don't think you actually need them all, it's not really important to know all of them.

The Allies during WWl included England, France, Russia, and the United States (they joined in the last year of war, but they still count!).