Desktop/Android/HTML5/iOS Java game development framework
Dust3D is a cross-platform open-source 3D modeling software
Cross-Platform C++ 2D/3D game engine
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
3D Procedural Game Engine Using OpenGL
Doom-based AI research platform for reinforcement learning
Free and open source real-time strategy game
Powerful, mature open-source cross-platform game engine for Python
A downloadable game for Windows, macOS, and Linux
Simple and light-weight 3D game engine
The open-asset-importer-library repository
Flax Engine, multi-platform 3D game engine
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Open source Cardboard SDK and samples
Parabator 2 - Free 3d board game
VR Mosaic - C++ Builder Applet v.2.5
GemRB is a portable open-source implementation of the Infinity Engine
Odamex is a free, cross-platform, modern client-server Doom engine
GLScene Engine for Delphi & C++Builder VCL Windows 32/64