Fast and lightweight JavaScript game engine built on WebGL and glTF
PyCAPGE - Python Classic Adventure Point and Click Game Engine
SDL based generic 2D game engine
Game engine supporting many 3D/2D formats and graphic effects
Mahasona engine is an open source game engine.
Built to be ease of use, with no programming knowledge, Multi-platform
Gorgon Game Engine (GGE) is a C++ game engine that handles many tasks.
Scriptable frontend for media applications.
Tween for Torque