These races are either not a major part of Escarnum's core and history, or are not included in the setting by default. However, they can easily be included in your campaign if you desire. If the group does not wish to add new races, this section also provides suggestions for replacing the desired race with an equivalent race from Escarnum's core.
Races which are not mentioned here can still have a place in Escarnum. Whilst Alm itself is fairly well-established, its neighbouring continents are largely unexplored, and even within it, wild places such as Kaath and the Barrens could easily provide new races a place to develop. Other races might be unique occurrences - magical experimentation with creatures was a common practice in the history of the Overseers, and there is the possibility that they might have created many other magically-altered hybrids and offshoots of the existent races.
Dwarves are a race which is not included in Escarnum by default. Essentially, the common roles of dwarves as a race - those of miners and/or craftspeople - is filled by the kobold clans. If the group wishes to include dwarves in setting, a good place for them may be as allies of the kobold clans, working side-by-side in the mountains; alternatively, they may be the technologically adept folk responsible for the ruins of Aethys, and some of their descendants still remain.
If the group does not want to add dwarves to the setting, a kobold of the Vaess clan may serve well in the role of a technologist or item-crafter. Alternatively, if the desired aspect is that of a sturdy, unrelenting warrior, an equitarn or gnoll should be a more suitable replacement.
Gnomes are not included in Escarnum by default. The appropriate replacement will depend on the role they are to play; some settings see them as tricksters, others as bumbling inventors, others as taleweavers, others as wizards. Indeed, the somewhat ill-defined identity of the gnomish race is a major reason for their absence from Escarnum's world.
In Escarnum, most of the gnome race's various roles are filled by the various clans of kobold, especially that of inventors. Alternatives include felbraug, for magic-using gnomes - a felbraug's psychic nature and small stature make it a good replacement. For bardic or trickster gnomes, the abilen is a substitute - they posess the same social grace, and the "light frame" drawback means they are essentially in the small size category.
Halflings are not included in Escarnum by default. In most settings, halflings are smaller and weaker than medium-sized races, yet known for their agility and social natures. In most cases, an abilen is the ideal replacement for a character who would be a halfling. Alternatively, both kobolds and felbraug match the small stature and nimble nature of the halflings, and can make excellent substitutes for the favoured halfling rogue.
Unlike most other races listed here, half-elves do exist in Escarnum. However, most halfbreeds take strongly after either the elven or human parent - and, since they do not breed true, half-elves are simply not distinct enough to be considered a race. Most half-elves or part-elves would simply be represented by using either the human or elf racial traits.
If an alternative to the half-elf is desired, the abilen is likely the best choice - half-elves often fill the role of skill-users and diplomats, both of which are the abilen's field of expertise.
Half-orcs do exist in Escarnum; they are simply not common enough to be considered a race, much like halfbreeds of other races, and are therefore not presented as a choice for Player Characters. The GM can allow a player to create a half-orcish character if they wish, but Escarnum half-orcs lack for any kind of cultural background or racial identity; a better choice in an Escarnum game would simply be to use a troll.
These mysterious creatures do exist in Escarnum, although to all but a few they are as yet unknown. The remnants of an ancient society that preceded even the elves and beast races, the warforged have been dormant for many, many years; now, gradually, they are beginning to awaken. A warforged PC will likely be the first of its kind to be seen in the world.