I have been working at a small team, so I am more like a 2D generalist. Concept art, characters, backgrounds, UI and promo art - this is all I deal with from time to time. Sometimes I do 3d low-poly modeling and texturing.
I was making Concept Art and Promo Art mostly. Also I was texturing.
And, sometimes I made low-poly 3d models.
I studied Graphic Design and traditional painting and drawing