I've been thinking a lot about different D&D settings lately and what makes them unique. Dark Sun is a post-apocalyptic setting where magic is destructive and halflings have become cannibalistic; Theros is based on Greek mythology where destiny determines your path, the gods are close to mortals and directly affect the world, and heroes adventure for glory itself; Spelljammer is basically D&D in space; Planescape jumps all over the planes of existence; Ravenloft is Gothic horror; Rokugan is Asian wuxia; I'm not really sure what Eberron is, something about noir and robots?
Anyway, with the release of Chris Metzen's Auroboros: Coils of the Serpent campaign that's literally just his own homebrew setting he made as a teenager in published form, I've thought about my own first setting I roleplayed in before I even knew about D&D: Argaenothruzil.