The Ren'Py Visual Novel Engine
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Free game engine for development of desktop, mobile, and web games
Stride (formerly Xenko), a free and open-source cross-platform C# game
Cross-platform 2D and 3D game engine with modular architecture
Multi Theft Auto is a game engine
A completely free, open-source, 2D game engine
Open source clone of the Age of Empires II engine
Multi-platform 2D and 3D game engine
Cross-platform game engine in Rust
A dead simple 2D game engine for Go
A cross-platform, open-source, pure C game engine for mobile game
3D C++ Game Engine - yet another open source game engine
2D Game Engine
2D Game Engine with Lua Scripting made on top of SFML
scriptable game engine with built-in support for 2D graphics and sound
Scripting language of the hawk game engine
cross-platform 2d game engine
OSGET is the first open source mobile game engine template.
Zen3D is a 3D engine and editor for creating games