There is a new interesting service for artists and game developers, TheBaseMesh.com. The new site contains 250+ base mesh 3D models in FBX and OBJ format all under the CC0 open source license. These can be used as the starting point for a sculpt or in a kitbashed 3D project. The models are low enough polygon they are appropriate for real-time 3D use, but have clean lines and UV mapping already done.
Details from the site:
Whether you need a mesh for Digital Sculpting, creating a High or Low poly model, Game Prototyping, draw-overs for concepting or any other creative endeavour, this asset library has you covered.
Every model adheres to real-world scale and comes with basic UVs, so you can get to making those all-important creative decisions faster.
ZIP files contain both .FBX and .OBJ files.
Best of all, the author intends to add 20-30 models per week and also takes user requests for future models to be added to the collection. The models are organized into categories and easily searchable.
You can learn more about THE BASE MESH and see some of the 3D models in action in Blender in the video below.