A chaos daemon invasion reduced the world's population down to the low millions, with most in a single city and scattered strongholds across the planet. The key theme of the setting is disparate people who used to be opposed to each other forced to work together. So a region could have what used to be a dwarf stronghold, but now there's drow and kobolds and giant beavers there too.
As such for the ancestries available it's probably something like this from most to least common
Humans (can have kids with anyone else because of genetic tampering by elves millions of years ago, so very populous and cosmopolitan)
Goblins (fungal aliens that hitched a ride to the planet with the elves, technically very few hivemind colonies but lots of bodies)
Halflings (very good at creating healthy communities because of magic they learned in the ice age)
Leshies (wood elves that turn into plants as they age, mixing into forests)
Orcs (blood elves that know ancient nomadic paths and are hard to kill)
Dwarfs (lack magic which is bad for protection, but they can eat anything and live underground)
Kobolds (scavengers that hitch their souls to powerful creatures or societies. look and act different based on that, big human populations make them look like dogs. with dwarfs they look like rocky little golems. etc)
Cursed (humans who don't know why they're supernatural, like vampires/werewolves/beastmen and assume it's because the forgotten gods cursed them)
Tieflings (lust elves, their carapaces shift and change to help them blend in and survive but they're mistrusted and often abused)
Goliaths (descendants of people taken as thralls by ancient giants, hardy but rarely accepted by the communities their forefathers once pillaged)
Drow (dark elves, they suffer from chaotic mutations that caused the ancient high elves to attempt mass murder against their own children)
Newborn Elves (the youngest race, elves in the past got speciated by the forgotten gods as revenge for their horrible crimes against the world to the four elves mentioned up above. only recently was that reversed when the elves helped the same gods beat back chaos, however...)
High Elves (almost none remain because for so long no new ones could be born, so despite their immortality they were functionally extinct. the reversal of their speciation came at the cost of that same immortality so now they're aging and dying out just as the first new generation is born)
This roughly goes down from millions to a few dozen.