Brief: This is not a comprehensive guide, rather a quick overview of the character races that populate the North and what stats fit them. All of the stats can be found in the core book.
Core Book: Mountain Dwarves (Dwarves)
Native northern Dwarves typically hail from the Regency of the Mines. They are known to be of strong and hardy stock. The Regent is known as a fair and shrewd ruler. He makes a good ally with the Human nations in terms of defense from threats such as Orcs, Goblins, and the Afridhi, but he also maintains a network of spies and informers amongst the Northmen and the Thonian Empire.
Core Book: High Elf (Cumasti), Wood Elf (Westryn), Half-Elf (Half-Elves)
Once a single people, the Elven nation had been shattered both by the political differences made by both the Western and Eastern branches of Elvendon as well as a magical curse that separates the group. The Eastern Elves, the Cumasti, are more common and are known or fair skin and golden hair. They are commonly in league with men in terms of a strong defense against an outside threat. Their interaction has also included producing children known as Half-Elves. Half-Elven children find little love among their Elven relations and will often be sent to live with Human relatives if available.
Elves of the West, or Westryn Elves, are dark haired and fewer in number since the Black Curse made it difficult for their bloodline to reproduce. Westryn Elves are militant and isolationist. Trespassers into western woods, including those of traditionally good aligned races are met with arrows and swords. Westryn Elves who are adventuring are expatriates that represent outliers rather than the norm of Westryn society.
Core Book: Rock Gnomes (Gnomes)
As far as the North is concerned, all Gnomes are Tinker Gnomes, associated with magic, clockwork, and steam. Gnomes little in the way of fiefdoms of their own. They typically share lands with another, such as Dwarves or Men. Gnomes are found throughout the North and the surrounding hills. The City-State of Maus has the largest of Gnome community, though there are sizable groups in Blackmoor, Mount Uberstar (the Regency), and Jackport.
Core Book: Harfoots (Halflings), Stouts (Docrae)
The Halfling community is divided into two groups as well. The eastern branch, known as 'Halflings', are a jolly folk who make their trade through their little boats and pony drawn carts. They love song, smoke, and food, with an emphasis on the food. They gladly share their fire with travelers.
Conversely, the Docrae have known nothing but woe as they have been harassed and exploited in the west. These deplorable actions have harden the hearts of the Docrae people, so they know little of comforts or how to express the kind of joy as their Halfling kin. They do know about war and revenge and are always looking to settle a score with spear, bow, or knife.
Core Book: Human (Thonian, Peshwah)
Humanity is divided into two ethic sub-groups. The native Peshwah are desert and plains dwelling folks with a strong horse culture and a varying tolerance for outsiders. Some Peshwah tribes are happy to accept neighbors and work alongside others, other tribes take to raiding and scorning the influence of outsiders on the land on their people. The Peshwah are often found in either the Plains of Hak or the Eastern Hak. Though nomadic, there are a few camps and border towns that Pesh will often stop in for trading or news.
Thonians are folk who trace their lineage from the North down to the southern lands, also known as the Kingdom of Thonia. Those Thonians who claim they can trace their bloodline to high nobility call themselves High Thonians. Few claim these titles, and fewer High Thonians would thing of rebelling against their home kingdom. Currently the Thonians are fighting each other as the North wishes to split from Thonia and have declared the North as the Kingdom of Blackmoor. Thonians are found throughout the western and eastern portions of the North.
Unearthed Arcana: Warforged (Clockmen)
Creations of the Gnomish people and often found in Maus, Clockmen are living constructs that are made of metal and touches of wood. The arcanum core in their chest has not only granted them function, but through either happenstance or fate, the magical energies have also granted them sentience. For the time being, the Clockmen and their Gnomish makers have lived in peace. However, as the years have passed since the founding of the Clockmen, the living constructs have begun to assert themselves and become more independent. Concerned parties hope that if a split does come between maker and construct that it would be peaceful, especially given the troubles growing west of Maus.
Core Book Race: Dragonborn (Dragonborn)
The Dragonborn of Rodhin are Draconic-Humanoids from a city where scale color plays a major determination in one's social standing within the hidden city. Reds and Golds are looked upon as leaders. Most other colors are viewed as commoners with some chances to rise of a higher station, scales such as blue or silver scales tend to move a lot faster compared to green or bronze. Dragonborn commoners with the least chance of success include the White and Copper scales. Dragonborn in general who do not wish to find themselves scraping by in a caste system will become adventurers.
Eberron Races - A link to the Eberron Races pdf that include 'Warforged.' Warforged is the template I used for Clockmen. You can get it: HERE.