John Nevarez is a visual development and storyboard artist working in animation. His projects include Monsters University and Cars 2, among others. He has recently left Pixar to establish a freelance career.
His long-running blog has examples of his work on various projects, as well as personal work, warm-ups and sketches for fun. Fun is the operative word by which I would describe his drawing style, particularly his line and tone drawings (which may be traditional pencil or the digital equivalent, it’s difficult to distinguish these days).
Nevarez has the kind of springy, lively line quality that makes it look like his drawings happen out of the pure fun of drawing, and just coincidentally are exactly what’s needed for the project on which he’s working.
In addition to his own work, for which you can see an overview here, his blog features work by other artists in the field, as well as a cornucopia of links to artist’s websites.