Forgotten Realms
From Marillia
The Forgotten Realms, often called simply the Realms, is possibly the most famous D&D setting currently. It is arguably the de facto "default" setting for 5th edition. It was made by Ed Greenwood around 1967. It's where we get Drizzt and Bane.
The main planet of interest is Toril, and the main region of interest on Toril is Faerûn.