The One Time is populated by maybe a dozen extant cultures, the rest having either died out or retired to elsewhere. Of those, only a handful can be found across multiple galaxies. The total population of these cultures number in the countless trillions, and all of them consist of multiple sub-cultures.
There is no single government or organisation which binds these cultures together. Even the Atharmi do not interfere with the running of civilisation, except where threats to civilisation as a whole is observed. Instead, there is a mixture of 'enlightened self interest' and 'might is right'. Wars happen, billions can die, and intervention may be immediate and extreme, or non-existent depending on how nearby cultures feel that intervention would benefit them.
The most important races from the standpoint of humanity are the following: