Plenty of options designed for straight D&D
Oathbound: (Arena, Wildwood) high fantasy high magic D&D
Valus: Gritty D&D
Rokugan: Oriental samurai D&D
Hamunaptra: Egypt Fantasy D&D
Twin Crowns: cool ritual system, age of exploration sailing D&D
Scarred Lands, post apocalyptic gods war D&D, tons of support products
Ptolus world of Praemal, short pdf on Ptolus' background world
Kalamar, in depth described world D&D
Codex of Erde: Medieval Germany with a dark fey vibe D&D.
Dog Soul Publishing's Mythic Settings, Baba Yaga Russia, Mythic India, Gallic France, Mythic Japan, Norse Legends,
Green Ronin's Psionic India setting, I forget the name.
Bluffside: High Fantasy in depth city
Don't know much about Wilderlands, Blackmoor, or DCC 35 except they are old school D&D themed.
Avalanche press' historical and mythic earth settings.
Ravenloft: Horror D&D
Dragonlance: knights and dragons, towers of sorcery, draconians
DragonStar: D&D in space
Northern Crown: D&D in fantasy colonial America
I'm sure I'm missing a few.
Nyambe fantasy Africa D&D, though it has alt classes for natives
Thieve's World, WoW, Everquest, Black Company, Wheel of Time, Conan, Slaine, all alter D&D to fit the settings