Pathfinder's qlippoths are based on monsters that first appeared in Green Ronin Publishing's The Book of Fiends: Armies of the Abyss for D&D v.3.0 (later updated to v.3.5 in the collected The Book of Fiends hardcover). Of the five qlippoths in that book (chernobue, hydraggon, nyogoth, Shiggarreb, shoggti), all but the chernobue were illustrated by Toren Atkinson. Lovecraftian monsters are one of his specialties, and i much prefer his original B&W drawings to the qlippoth illustrations in Bestiaries 2 and 6. I've included links above to two of those images, which he has shared on his website.