Fast and lightweight JavaScript game engine built on WebGL and glTF
Open source library for creative expression on the web, desktop, etc.
Game engine supporting many 3D/2D formats and graphic effects
Amateur 3D Game Engine
Vivid3D is an open-source 3D engine with powerful 2D UI.
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Modern 3D engine and IDE written using C# and C++.
A 2D game engine and level editor
Source code of the chapters of the book 3D Game Development with LWJGL
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
.NET - VISUAL BASIC NVIDIA +ATI PHYSX SLIMDX DIRECTX 9 -ENGINE/WRAPPER
Mahasona engine is an open source game engine.
Cross-platform C framework very compact libraries and tools.
A basic 3D environment with a first-person POV
A cross platform 3d c++ game engine