Pech

Pech are subterranean humanoids with some Earth-working magical ability, especially in groups. They were introduced in The Lost Caverns of Tsojcanth. They haven't done much in the printed modules; the niche of not-awful Underdark critters was long-established already in the svirfneblin.

They are four foot tall, jaundiced and scrawny, with pupil-less eyes. Pretty much what a D&D-playing nerd grows up as, after his inevitable descent into introversion and alcoholism.