Non-Monarchy? Non-Colony? Democratic? What do you mean by free?

Great Britain. The original basis for the revolution (to the best of my knowledge) was that the colonists were being denied their rights as British citizens.

Depends on your definition of free. If you mean non-monarchs then many Italian trade cities were republics run by powerful families. Also many large empires had a tenuous grasp on their territory and many would have very little notion they were ruled by anyone.

Half a million slaves do not a free country make.

European powers with high living standards and some degree of personal liberty often controlled slave colonies too. Others had large serf populations.

Freedom was too often an accident of birth: freedom for some.