JCAB CAD Solutions - Offers CAD libraries of fasteners, nuts, washers, and bolts, in DWG and DXF formats. - http://www.jcabcadsolutions.com/
Archiforge - Free 2d, 3d cad models, textures, a gallery with projects as well as information about the latest architectural competitions. - http://www.archiforge.com/
Human-Ergo - A source for poly-faceted 3D Models of human figures, cars, trucks and construction machinery for SolidWorks, Unigraphics, SolidEdge, and IronCad. - http://www.human-ergo.com/
PARTserver - A parts library integrated with many CAD systems for direct invocation, as well as with standard data formats - http://www.partserver.com/
Oh Yeah CAD - A free online parts library that supports AutoCAD, Solidworks, TurboCAD, and SolidEdge native file format. - http://www.ohyeahcad.com/
Catalog Data Solutions, Inc. - Solutions to add 3D models to online catalogs and CAD modelling consulting. - http://www.catalogdatasolutions.com/
VirtualCAD - Free 3D CAD models in tandem with Free manufacturer part number interchanges. Supports all major CAD systems. - http://www.virtualcad.com/
CADRegister - A source for design professionals, engineers, and architects to download component drawings from leading manufacturers, in a variety of industry-standard formats. - http://www.cadregister.com/
Catalog Data Solutions Inc. - Online 2D/3D parts library hosting, integrated with PTC Wildfire and the ability to do Parametric searches. Formats include PRT, DXF, IGES, DWG. - http://www.catalogds.com/
CADSymbols - Online 2D/3D parts library for Solidworks, AutoCAD and other software, in formats including ACIS SAT, DXF, DWG, and IGES. - http://www.cadsymbols.com/
CADParts - Produces library symbols and footprints for the Cadence CAD software. - http://www.cadpartsusa.com/
Trace Parts - Library of parametric components for 2D/3D CAD assemblies, which can be used with several CAD packages. - http://www.traceparts.com/
PARTsolutions - A parts library integrated with many CAD systems for direct invocation, as well as with standard data formats. - http://www.partsolutions.de/index.asp?sid=2
Vanguard Software GmbH - Offers partsCAT, an electronic spare parts catalogue software for publishing catalogues on CD-ROM and online. - http://www.vanguard.at/en/
CADClick - A database for mechanical engineers that offers access to CAD geometries from different suppliers on mechanical engineering. - http://www.cadclick.de/