Cergorach
The Laughing One
Dragonlance:Drow don't exist in Dragonlance, Dark Sun or Mystara. They are very different in Eberron. Orcs don't exist in Dragonlance, Dark Sun and until recently, Ravenloft. Duergar have no known existence on Mystara, Dark Sun, and I don't think Dragonlance.
Drow
Drow are a race of elves that dwell primarily in the underdark. They earned a reputation as evil people, although some with a neutral disposition do exist. On Krynn, "Drow" is merely an elven word describing a Dark Elf. You can see a dark elf in the The Soulforge (Super Endless Quest) game book...
Daergar Dwarf
The Daergar (Deepest) are one of the Clans of Dwarves who live in the underground kingdom of Thorbardin. They are closely related to the Theiwar clan and are considered “Dark Dwarves”, some clans even refer to them as “Dewar” due to inter-marriages between them. Their numbers are plentiful, and...
I specifically didn't mention Dark Sun.
Different in Eberron, maybe, but they're there.
For Mystera, you're right about Drow and Daegar. I thought of some similar things that aren't the same at all.
I don't care about a generic human statblock, I care about a (human) Bandit, a Mage, Cultist, etc. And while there was a generic statblock for "Drow" in the MM 2014, there were also Drow Elite Warriors, Drow Mages, and Drown Priestesses of Loth. Specific NPCs. For the MM 2024 Drow could be easily renamed to Drow Warrior. Humans is also a PC species, and the Mage is still there and the image of that one is definitely human... And if they wanted to just not use the word 'Drow', Warrior of Loth, Elite Warrior of Loth, Mage of Loth, and Priestess of Loth. But they kept those names in Adventures in Faerun (Drow).

