In mine, it is the same but with lizardfolk and kobolds due to similar dietary needs.In my homebrew setting, Dragonborn have a civilization vaguely akin to the Phoenicians/Carthage. They rule a loose confederation of city-states and are kings of maritime trade. They are also occasionally find themselves at odds with the dominant empire (that's a blend of Imperial Rome, Maurya India and Achaemenid Persia). Their cities are very cosmopolitan, with a large human cohort and a sizable halfling presence (the halfling population nearby are nomadic pastoralists, but some are curious about life in the cities).
There is most to species that your PC.What would the players gain if all of them were equally prevalent in a setting? The fact that they are already a part of that setting's standard line-up of PC species should be all that matters when choosing one of them for your character. You choose a species and pick a place within the setting for them to hail from.
Shared experiences and history, speaking similar language, finding racial and class magic items, etc, epitomizing or bucking class or species biases and stereotypes.