There are thousands and thousands of good sculptors out there who have the occasional great sculpture, but very few consistently great ones. The below artists represent the cream of the crop among character sculptors and the standard you want to be reaching for as a digital sculptor.
http://kentmelton.blogspot.com (do a pinterest/image search and you'll find much more)
(His industry-focused sculptures are all in the "Client" menu, with each project)
Also look up
Michael Defeo (just do an image search)
Jerome Ranft (do an image search for "pixar maquette" as he and Greg Dykstra do most of them)
Greg Dykstra (the other maquette sculptor at Pixar)