The source for the above is Sword Coast Adventurer's Guide for 5e + Races of Faerun for 3/3.5 plus in the case of "Dark Elves" just my observations from lady penitent
Mmh! I do find it curious the large masses of people claiming that elves are 'white and blonde' and 'too caucasic'. Then you read the descriptions and you find out that the vast majority of them aren not actually white and blonde. There are so many possible combinations, from blues and green hues to very dark skin. Wood elves per instance are said to be the most populous of elves, and they're tan, and dark haired mostly.
On your thoughts about giving subraces ethnic hints, a random thought that occured to me was this elven depiction of 5e Player's Handbook:
She has the classic angular features, but also... Do I have a big imagination, or she kind of looks like Rihanna? :'D This is an excellent example of an ethnic looking elf, in my opinion.
Not just you. Totally looks like a Rihanna-Elf!
Originally Posted by blindhamster
I think using inspiration from African ethnic groups would work well for Wild Elves, Copper Elves would probably be more like mixed background people because Copper Elves are exactly that, a mix of Wild Elves and the other Elven types. Greek ethnic inspiration seems like a good fit for Sun Elves IMO. Moon Elves and Star Elves physically are probably the ones to give the more anglo caucasian appearance. If the were to branch out further, I'm not sure about "asian" (which is a very generic term sadly) inspiration for any of them, Eladrin might be an interesting one to consider tying a bit of Japanese influence to, considering their art in Volo's Guide. Drow would potentially fit following the same pattern as Wild Elves, considering their background as the Dark Elves were originally from the same regions as the Green/Wild Elves.
However, with all the above, I think you'd still want to:
adjust eyes to be more almond shaped
add sharper, more angled, more defined jawline and cheekbones
make the nose a little narrower
reduce chin width to accent the more angled jawline
increase the angle of brows slightly
make the face a bit more slender
I like your ideas and would be happy to see something like this in-game in the future