Out of the Abyss
There is no canon setting. Make up any place (country, city-state, etc) of origin you want. It can be from the surface or underground.
Races: Any from players handbook including drow; plus orc, goblin, kobold, and deep gnome.
Alignments: Any except Neutral Evil and Chaotic Evil.
Ability Scores: Use either the supplied array or 27 point buy.
Start at 3rd level with max hit points. Make your back story to reflect this. Your characters are already somebody accomplished; either heroic or criminally (but not villianous).
Equipment: roll 1d20+ 1d10. I'll tell you what it means later.