Worldbuilding notes - Steampunk D&D 'verse
*Most of them are lactose intolerant. How are you going to keep cow pastures underground? (Well, the underdark does have mammals in D&D, but drow dairies just don't make much sense to me.)
Female drow tend to become a fertile at a relatively more mature stage of physical development compared to human women. This is due to both the slow reproductive patterns of all elves (drow actually tend to have more children on average, due to higher attrition rates), and the fact that even fully grown drow women tend to be skinny little things, but dark elf babies would probably not be much smaller than those of humans.
Infanticide is actually quite rare (at least of one's own offspring). Female drow all learn how to control their own fertility (something like biocontrol, a la Vonda McIntire?), and they have sex-predicting divinations that work reasonably reliably after the second month. No drow woman is going through all the trouble of labor for a child she doesn't intend to keep for a while.
Drow belong to their mother's lineage and take her clan name, except under outstanding circumstances (like wanting to distance oneself from a matriarch just executed for high treason, say).
As well as the standard issue keen elven sight and hearing, and seeing in the dark, drow have more sensitive noses than humans or even surface elves. Most subterranean races have better senses of smell than their surface-dwelling counterparts.
Fruit, green vegetables, sugar, and alcohol are all expensive delicacies in drow country. It probably amuses surface-drow how much humans are willing to pay for truffles, since back home subterranean fungi are a staple food. Depressing as the prospect is (at least to me), their biggest source of mammalian meat is probably some kind of giant underground rat.
They know about gunpowder, and probably some of their alchemists study it in an attempt to keep up with the dwarves, but most drow don't like it. The noise and the smell probably have something to do with this.
There are actually a fair number of defectors (men and women, but more men), but most of them aren't Chaotic Good, famous, or practitioners of a flashy fighting style, and prefer to just keep to themselves, and enjoy the relaxing atmosphere of a society not constantly being poked at by a bossy Chaotic Evil divine arachnid-woman. (One of the constant themes of this universe is that evil people, unless they're a particularly well-organized sort of Lawful Evil, usually don't like each other very much.)
Women and men grow their hair long, but style it differently.