CGTrader - CGTrader is an online marketplace at which artists can sell and buy Revit and 3D models.
3DOcean - 3D Models & Accessories From $1 for 3D Models, Textures, Materials & Shaders, 2D Concepts...
Free3d - Free3d (previously TF3DM)
TurboSquid - TurboSquid offers 3D models for professionals.
3Dmdb - 3Dmdb is a search engine-based hub of multiple three-dimensional colorful objects which can be downloaded, purchased, and rendered from shops or marketplaces.
SketchUp 3D Warehouse - The place to share and download SketchUp 3D models for architecture, design, construction, and fun.