some ebooks i posted onhttps://warosu.org/ic/thread/2479248
Nuthin' But Mech: Sketches and Renderings
Daniel Simon - Cosmic Motors - Spaceships, Cars And Pilots Of Another Galaxy
Carl Liu Sketchbooks vols 1&2
Nenad Pavel - The Industrial Designer's Guide to Sketching
Charlotte & Peter Fiell - Industrial Design
Keith Thompson - 50 Robots To Draw & Paint pt 1,2 & 3http://hardsurface.tumblr
i also have a folder with tons of mech and 3d inspo i'll might upload it later.