The Known World of the Barbaric Frontier is mostly populated by humans as are typical worlds of sword & sorcery genre. However I couldn't resist to use standard high fantasy races like dwarves, elves and halflings(because my love for the dwarves).
Haflings are the most widespread demi-human race in the Known World - their population is app. 100 thousand, their communities could be found in the biggest cities of the continent. They mesh with the social landscape pretty well, however, humans will never treat them as equals.
Dwarves are the second most populous demi-human race in the world, app. 60 thousand of them live scattered on the continent. Their are considered curiosity, nothing more.
As for the elves - their population is app. 15 thousand and all of them live in the Barbaric Frontier. In most parts of the Known World they are mere legend.
Human population of the Known World is around 50 million people for comparision.