Alliance of Worlds
The Alliance of Worlds is an intergovernmental organization to confront common challenges, develop cordial relations between member governments, and maintain intergalactic peace and security while allowing member governments to retain their own autonomy and sovereignty.
During the Galactic Civil War against the Galactic Empire they were known as the Rebel Alliance. Post wartime, the leaders of the Rebel Alliance realized that a single government couldn't effectively govern an entire galaxy. It was too many worlds, too many people at one time. Instead they formed the Alliance of Worlds.