CGTrader, Pinshape, ...
Turboaquid, Unity Asser Store, ...
Autodesk Gallery, 3D Mili, ...
Free and payable 3D models are categorized in different classes based on their application. Below classification, which introduce 3D model provider sites, helps you to easily find the 3D model you're looking for. At first you should determine the application of your need (for 3D printing, for animation or architecture)
CGTrader is a marketplace to buy and sell 3D designs. Not just limited to CAD files, however; the site also offers a selection of free 3D printer files to download for production on any 3D printer.
It allows designers to share and sell their 3D printable designs, and people with 3D printers to print those designs on their own printers.
Download many free stl files for 3D printers. Share in open source or sell your 3D printable files.
Thingiverse is a website dedicated to the sharing of user-created digital design files. Providing primarily free, open source hardware designs licensed under the GNU General Public License or Creative Commons licenses, users choose the type of user license they wish to attach to the designs they share. You can find some free 3D printer files in Thingiverse.
Turbosquid 3D models include various categories like people, animals, airplanes, food, and drink,... You can also find free 3D models there.
CGTrader is a marketplace to buy and sell 3D designs. Not just limited to CAD files, however; the site also offers a selection of free 3D printer files to download for production on any 3D printer.
Unity asset store helps you deploy your game sooner and start making money faster by providing a vast range of game characters.
Archibase planet lets you easily find 3D architecture models and download them. Also, it provides you a feature that you can look for 3D designers in your country and contact with them. This is an excellent feature.
This is what Autodesk says:" Inspire with your story and let other designers, engineers, and inventors spark your creativity." In Autodesk gallery you can share your projects with the world and get feedback.
With 3D mili, you can easily Search between various categories including decoration, furniture, lighting, kitchen, bathroom, childroom, etc and download the 3D architecture model you're looking for.
Turbosquid 3D models include various categories like people, animals, airplanes, food, and drink,... You can also find free 3D models there.