One of the best things about writing fantasy is the ability to create cultures and peoples, and one aspect of that - though far from the most important - is physical appearance. Now, I know racial type is a hot-button topic in fantasy, with some people increasingly concerned about how the genre is white-and-European-centric, and arguably even some characters who are physically different are just western folks "painted" - but I'm going to skirt that issue in this post, just as I skirt it in my writing. Not because I'm afraid or unaware of controversy, but because ...
... why limit yourself to Earth types? Some components of physical appearance are tightly tied to evolution and adaptation to a particular clime, such as skin color and physical type - that is, longer, thinner body types disperse heat better and are more suited to hot climates. Others, however, have no correlation in necessity. Genetics may have a hand in it, dominant traits coming to the fore ... but who says that the same traits have to be dominant or recessive in your world? If magic gets to be a gene (and in some worlds, it really is), why not play further with the rules of inheritance? Why not make a culture / race that has no direct parallel in the real world?
I've done this in several different ways. Mixing up types in a way not usually seen in our world is one. The Alayins, the dominant people in "Journal of the Dead," are dark complected with light hair and eyes. The few dark-eyed characters are treated with some fascination by the cast. Another way is specificity - for instance, a race that only produces blondes. Or capitalizing as a physical or cultural feature something that isn't usually considered part of a distinct type. On Trianor, the Sikan standard of beauty revolves around the feet. A final way is simply to pick something that doesn't exist in the real world - genuinely yellow eyes, dominant polydactylism ... actually, I think I'm going to mark that for future use - and make it racial.
When I do imitate an Earth type, it's either out of laziness (I admit it!), or because I want to evoke a specific parallel. For instance, in the world of the Seventeen Seas, Ilkanae is supposed to be reminiscent of ancient Greece, and the reader should get that feeling quite strongly. And in "Who Wants To Be A Hero?" the parallels were necessary both for the feel of the story and to support some of the real-world cultural / mythological jokes. Destia is basically pre-Revolutionary America if it were a Greek colony instead of an English one ... well, okay, that's not exactly a parallel ...
This all comes up because I've been editing "Scylla and Charybdis" and noticed Gwydion has brown eyes. There was a time, when I was a young writer, when I hated brown-eyed characters. Part of it was because I didn't see any variety in it: you could have brown eyes, hazel eyes or ... brown eyes. Later, obviously, I realized there are a lot more variations. Another part of it, I think, was self-identification. I have grey eyes, which tend to greener or bluer depending on what I'm wearing. Yes, I am this close to being the fantasy cliche of the girl with the mood-ring eyes.
Sidebar about "Scylla and Charybdis:" I very consciously mixed real-world ethnic types (since it's science fiction) with both appearances and names, as a demonstration of how those types had fused over the centuries. To do it to every character would have made it look like a circus, but there's a reason I have a redheaded Upala Manuel. The city of Nissyen has a mostly-assimilated Native American population - but this is never said directly in the text. It's left implied with the names and faces.
Back to the brown-eye controversy, I actually started consciously forcing myself to create characters with dark eyes, and I was all proud of myself when I had a narrator as such. Yes, I was young and silly, but it's a place I came from and a door I used to have shut for no other reason than instinct. Now I like exploring unusual combinations, not as a way of making the characters superficially special or diverse, but as one more way of expressing the possibilities of a secondary world fantasy ... and reminding readers that they're not in Kansas any more.