The Blueprints is:
a website dedicated to collecting 3/4/5-view drawings, templates and blueprints for as many objects as possible. Ranging from humans to tanks and cars to mobile phones, the goal is to provide reference material for 3D modelers, scale modelers, replica builders etc.
That's right - a very large repository (37,000+) of vector drawings mostly of cars. And tanks.
The drawings are stored in Illustrator, DPS, PDF and SVG formats. Nope, they are not 3D models - but they could be of great use to 3D modellers who need to create 3D designs. Of cars. Oh, to be fair, while the site seems to have drawings of practically every vehicle ever made or imagined, it does have airplanes, humans and a few other types available. The FAQ also states you can potentially sell 3D models there, too - but we had a difficult time finding any. But there's plenty of cars!
The site operates as a clearing house - you can place your drawings for sale, and The Blueprints will skim 35% off of any purchases made. Registration is free, however.
Via The Blueprints (Hat tip to Kerry)