Hmm. As far as my main, most-developed home campaign settings go....
1) Azeria - Drow are good and crazy here, like they ought to be. Sadistic, self-serving, conniving, always trying to get an upper hand and lord it over everyone else, but generally just trying to get away with as much wicked fun and plundering as they can without getting caught/killed.
Mostly like the core-rules drow, no spider-fetish though, no Lolth, instead their patron goddess is Luna, Goddess of Night and the Moon, patron of assassins, thieves, and spies, among other things. Still, the drow of Azeria make significant use of monstrous spiders and other poisonous insects, and driders are cursed drow as normal. Half-fiendish drow are not that rare, either, and the drow make deals with all kinds of creatures to further their personal agendas.
Good drow in Azeria are almost unheard of, since they're naturally inclined to villainy, and it takes a lot of effort to make a drow child grow up into a halfway-respectable person, if anyone even wants to bother trying. The evil drow have enclaves in many parts of Azeria, mostly underground, but they also control a significant portion of an evil empire along the eastern edge of the main continent.
2) Rhunaria - There aren't 'drow' per se, but there are dark elves, with roughly the same appearance as the drow of the core rules. Dark elves are a Lawful Evil society in Rhunaria, the creation of an earlier elven Mage-King, who experimented on all kinds of creatures, even other elves. Dark elves are one of the two elven subraces created from those experiments (the other being aquatic elves, who were sort of a failure, retaining their original minds and free wills).
The Mage-King transformed some elves into dark elves to empower their spellcasting ability, making them the most effective casters in the elven army. And the process also made them completely loyal to the Mage-King's will, even in later generations of dark elves born from the first ones. However, a few dark elves are born without the instinctive compulsion to behave according to the ingrained doctrines of the Mage-King, a fluke of nature or Rhunaria's abundant magical forces. These few have the potential for chaos or good, but more often than not simply tend towards neutrality, finding their comrades' attitudes strange and unnatural. They tend to be more selfish and wary than other dark elves, but the dark elven society still makes most of them become some shade of Evil, or Lawful Neutral.
Rhunarian dark elves have a sort of Middle Eastern and sort of Indian flavor, though their leadership is a magocracy rather than a theocracy. Arcane power is of utmost importance to Rhunarian dark elves; one cult-like organization of sorcerers among them, the Sons of Ishala, is well-known for dealing and breeding with fiends to increase the magical talents within their bloodlines. However, it is a wizardly organization that leads the dark elves, founded by the Mage-King's closest advisors and servants after his disappearance. They use titles like bey, shah, and emir to signify their rank within the magocracy and the guild.
Other arcane groups are more like lesser nobility, while the remainder of dark elves are mostly looked down upon as grunts and laborers, even though many are skilled soldiers, shamans, assassins, and more. The ones who actually strike out most of the time against surface-dwellers. Religion is treated as something important in dark elven society, but it's largely lip-service, with arcane practices considered more important and useful.
The dark elven priests serve the Spirit King, though priests are rare amongst their kind, and they consider it a sacred duty to enslave the other races and subjugate them to the enlightened ways of the dark elves, as well as to bring the other elven subraces "back into the fold" as minions of the Mage-King's will and the supposed gospel of the Spirit King, since the jungle elves and aquatic elves each went into hiding after the fall of the Mage-King's dominion. In truth, the dark elves are just clinging to the old ways of the Mage-King, from the last glory days of their kingdom, and hiding underground to avoid the collective wrath of the humanoid and monstrous races their kind had once enslaved. Trying to build up their numbers and arcane powers to someday reclaim the surface from the non-elves.
Rhunarian dark elves have different stats (and no ECL) compared to the core rules version.
3) Aurelia - No 'drow' here either, but there is a subculture among elvenkind, a scattered group of elves that have largely turned their back on Nature, and are called "dark elves" by others. They look like any other elves, but develop a few different traits as their traffick in dark powers and seek personal superiority, shunning Nature which shuns them in turn. The dark elves have some dealings with the dark fey of the Unseelie Court, but are still largely independant and self-motivated. Any elf can become a dark elf, though few do. Their lore and supernatural powers are forbidden among other elven societies.
Their tapping into dark powers makes them sneakier and better spellcasters to an extent, but has some drawbacks as well. Dark elves generally live alone or in small enclaves, far from other elves, since their tainted aura is easily detected by fey, priests, and paladins. They're explicitly nongood in alignment, though they don't necessarily have to be evil. That's just where the so-called Dark Road tends to lead them. Dark elves can use magic or psionics to try and mask their auras from detection, but fey can always sense their taint on sight, regardless; no dark elf can hide its betrayal of Nature from any true spirit of Nature. Nonetheless, it is fairly easy for them to plot and work in secret among non-elven societies and even some elven ones.
Aurelian dark elves are just normal elves that have taken one or more feats along the Seeker of the Dark Road feat tree.
