GemRB is a portable open-source implementation of the Infinity Engine
A Complete WebGPU Game Engine for Browser & Desktop Arcade Oriented
Orx: Portable Game Engine
Game engine supporting many 3D/2D formats and graphic effects
Portable game engine with main focus on point-and-click adventures
scriptable game engine with built-in support for 2D graphics and sound
Free Android 2D OpenGL Game Engine