Complete Transformers: The Ark, aka Transformers: The Complete Ark, compiled, restored, designed, and written by Jim Sorenson and Bill Forster. Out of print.
From the publisher:
Both sold-out volumes of Transformers: The Ark are collected in this must-have compilation of animation models and character designs from the classic Generation 1 era Transformers!
Part One features designs from the four seasons and one movie of Transformers. In addition to well-known characters like Optimus Prime, Megatron, Bumblebee, and Starscream, you get animation models for one-shot characters like Scamper, TORQ III, and Devcon, and even characters who never appeared in animation.
The second part covers the Japanese material like Headmasters, Victory, and Zone.