I've created a D&Dish game and I've long since pondered how to handle what my humans look like.

One idea was just to go the Tolkien route and everyone looks like northern European. Another was to do what Rich Burlew seems to do where each major continent seems to have it's own general appearance. One thought I had was because I created a lot of nations that are based on English style feudalism and a lot of nations based on Japanes style feudalism that I would make the northern hemisphere Cauasion and the southern hemisphere Asian.

Then I came up with something more exotic. The four "races" of humans and demihumans are Fire, Earth, Water, and Air.

People who are born near the equator (where it's warm) tend to have fiery traits. People who work with their hands for a living tend to have fiery children.

People who are born near the poles (where it's cold) tend to have airy traits. People who live nomadic lifestyles tend to have airy children.

People who are born far inland tend to have earthy traits. People who tend to live off the land tend to have earthy children.

People who are born near the coast tend to have watery traits. People who live off the sea tend to have watery children.

Certain places are fonts of magical energy (volcanoes, enchanted springs etc) tied to one of the elements which causes the locals to adopt the elemental traits of the magic font.

Mixed races is certainly possible. Children tend to pick up a third of their mother's elemental influence, a third of their father's elemental influence, and a third of their environment's influence.

Common Hair traits
Fire: Red, yellow, or orange. Frequently frizzy or cowlicky. Children and adolescents often have highlights or accents of shocking colors like purple or blue but this usually disappears by adulthood.

Earth: Brown, black, sandy blond, sometimes vaguely metallic. Straight, tangle-free hair is the norm.

Water: Various shades of blue, sometimes green or black. Hair is usually wavy and shiny.

Air: White, grey, silvery (like the moon), golden blond (like the sun). Hair is frequently curly like fluffy clouds.

Common Skin Tones
Fire: Bronze or in extreme cases orange.
Earth: Various shades of brown or grey. In extreme cases very dark shades of brown or grey.
Water: Light blue with a hint of green. In extreme cases, slightly silvery.
Air: Caucasian pale. In extreme cases, literally white or semi-translucent.

Stereotypical Body Type
Fire: Medium build, medium height
Earth: Short and stocky
Water: Lithe and curvy
Air: Long and lanky

Common Eye Colors
Fire: Grey is especially common. Red, yellow, purple, and black are known.
Earth: Brown is especially common. Black, green and various metallic shades are known.
Water: Green is especially common. Blue, grey, and brown are known.
Air: Blue is especially common. Silver, gold, grey, and purple are known.

Stereotypical Noses
Fire: Especially round
Earth: Large bridges
Water: Small and pointy
Air: Large nostrils

The Ravages of Age
Fire: Unlike everyone else, hair and skin get darker instead of paler. This is nicknamed “cindering.” Fiery people tend to retain their muscle mass into old age well but they accumulate aches and pains more often than the other three.

Earth: Discoloration and body settling is much less pronounced than the other three. Wrinkles become very pronounced compared to the other three. The word “craggy” gets thrown around a lot.

Water: Wrinkles and skin damage occurs much slower than the other three. Unfortunately, watery people tend to get fat and lose their figures and muscle mass faster than the others. They are said to “flow down hill.”

Air: Airy people generally avoid getting wrinkles and chronic pains. They very rarely face senility. Hair loss is much faster than the other three. Discoloration is more pronounced than the other three. Elderly air people tend to become gaunt much faster than the other three. They are said to “fade away.”

Negative Cultural Stereotypes
Fire: Hot tempered and hot headed
Earth: Stoic and boring
Water: Manipulative and indirect
Air: Flighty and Unpredictable

Positive Cultural Stereotypes
Fire: Brave
Earth: Hard Working
Water: Empathetic
Air: Creative

Primarily I have humans in mind with this, but I don't see why it wouldn't apply to demihumans. Just from their lifestyles, most dwarves would be very earthy with a dash of fire. I do have a small group of seafaring dwarves but they are a very tiny minority.

I'm not sure if this should apply to monsters and monstrous races. In ancient times my world had a massive elemental cataclysm. The few races that have ancestors that date to before the elemental cataclysm (mostly dragons and dragon-like monsters) would not show elemental racial features at all.