An out-of-character answer for this one: I apologize for writing this early in the morning with a caffeine rush. So it may ramble on a bit.

The exact composition of the Borderlands is a bit complicated and not something I've fully set in stone. I've got a general idea that I'll lay out here:

1. Humanity (Terrans) is the most numerous race. It isn't the classic human as we envision it, but it's not too radically different either. If we had to gamify the concept, it would be the Varrient Human option in a DnD 5e game rather than a simple baseline.

2. Next are the Small Folk, your Hobbits, Kinder, and Gnomes. Technically, they are all different races/ancestries, but they are grouped together as they are all descendants of ancient Fey.

Hobbits are the most numerous of the three and a bit taller and stockier than their kin. They are often called halflings as they seem similar to humans in shape and culture. They are the most distant from their Fey ancestry.

Gnomes often form smaller, tighter groups called 'clicks' living in sections of the city they have carefully plotted out as their own. Gnomes have stronger ties to their fey ancestors than Hobbits, which shows in their colorful hair and affinity with magic.

It's hard to pinpoint how many free-spirited Kindred exist, as they retain the primordial Fey blood their kin have lost and emulate many of the odd behaviors of the illusive Fey. They are tricksters, kleptomaniacs, with no sense of fear and a bizarre sense of right and wrong, making coexistence difficult. Still, there is (usually) no malevolence in their behavior, and unlike the Fey, they can at least understand how 'mundane' beings think and operate.

1. Elves were once counted among the Fey, but after the Shattering, they lost their immortality and connection to the Arch Fey who had blessed them. Despite this, the Elves of today still have many of their ancestors' gifts, including sharp sense, lithe yet powerful bodies, stunning beauty, an innate gift with magic, and a long life. Elves are as diverse culturally and ethnically as Terrans, but in the Borderlands, Elf has three main races.

The Edlon are Elves from outside the Borderlands, those who have adapted to the broader culture of the Tsardom of Markovia but still retain some of their traditions and culture. They are the most numerous of the elves and the ones most commonly encountered in cities and towns.

Pereldar, better known as Half-Elves, are those who have a trace of elvish heritage. This can be as recent as one generation or as distant as ten; thanks to the dominance of Elvish genes, they always inherit dominant elf traits that grant them most of the gifts of normal elves: Shapr senses, a lithe build, and an affinity with magic. They do not live as long as their kin, but they do live longer then most other races around them.

The Hísimë are the "mist elves" who once ruled over the Borderlands, but now are confined to the wilderness and the Mist Wood. Physically, they are paler than Edlon Elves, but little else differentiates them save their culture. Their numbers are unknown, though a shaky truce extends between them and the Tsardom's forces in the Borderlands.

1. Dwarves are physically short, resembling stocky Terrans, but they are much more dense and muscular with a strong tolerance for poison, flame, cold, and disease. Dwarves have shaper minds that can tabulate the value of things quickly and have long memories that do not wither with age, which is impressive considering they can live for centuries. To owe a dwarf a favor is to forever owe a debt, as it is said. They are not as numerous as the other races in the Borderlands, as most Dwarves prefer to look down on those below them from their mighty fortresses above the clouds. Yet, where there is profit, you'll often find a Dwarf.

2. Sekmins or SerpentFolk are, as their name implies, a blend of snake and Teran created in a blasphemous ritual over three centuries ago. How serpent-like a Sekmin depends on its house, with the ancient and venerable houses being snakelike abominations and the newer lower houses retaining more human traits. In the Borderlands, no major House is represented, but this has given lower houses a chance to grow in power and wealth, usually through control of Guilds or having the appointment to positions of power by the Imperial Court.

3. Kobolds are small reptilians who have some traits of the ancient Dragons that were said to have shaped them. They are the self-proclaimed inheritors of dragons and can be found throughout the Borderlands. Some clans live peacefully in cities and towns, filling a niche as tinkerers and scouts; others live separately, seeking to find a way to bring back or at least harness the power of their long-dead masters.

4. Orcs trace their creation to the Great Kingdom of Lazica, one of the first and most powerful nations to rise after the Shattering. Their empire stretched across much of what is now the Tsardom of Markova, and they were adept at rediscovering and unlocking the secrets of the Silver Age. This included "controlling the wellsprings of life," which allowed them to create new species, the most notable of which was the Orc.

The first Orcs were not born but grew, standing among the first of the Dryads. A mixture of humans and plants. Orcs were the loyal and fanatical foot soldiers of Lazica carrying their banners far and wide but would ultimately outlast the Great Kingdom. Lazica died a slow death of internal rebellion, outside invasions, and monstrous incursions of their own design. With their old home destroyed, Orcs have spread far and wide, taking up residence in every corner of the world.

1. Lizardmen are large reptilians hailing from the labyrinth under the earth. They have powerful builds and scaly hides with eyes that can see into the low infrared spectrum. Their numbers are unknown as their society is chaotic, to say the least; with might makes right as the ruling philosophy among them, there's little need or effort to record history or collect a census.

There are more, but these are the most numerous races. I'll no doubt add and subtract from this list as I develop the idea.