Verge3D - Practical framework for creating 3D Web applications
Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.
PlayCanvas - PlayCanvas is an open-source game engine built on WebGL and WebVR.
Open 3D Engine - Open 3D Engine is an open-source 3D game development engine in real-time.
Sketchfab - Sketchfab is an industrial design software tool is useful for ideation and for beginners in the industrial design field.
WaveEngine - The definitive free cross-platform mobile engine to unleash your games using C#.