Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Verge3D - Practical framework for creating 3D Web applications
FreeCAD - An open-source parametric 3D modeler
PlayCanvas - PlayCanvas is an open-source game engine built on WebGL and WebVR.
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
Sketchfab - Sketchfab is an industrial design software tool is useful for ideation and for beginners in the industrial design field.