libtwo - All-purpose c++ app prototyping library, focused towards live graphical apps and games
SFML - SFML provides a simple interface to the various components of your PC, to ease the development of games and multimedia applications. It is composed of five modules: system, window, graphics, audio and network.
Grit Game Engine - The Grit Game Engine is an MIT-Licensed Open Source Game Engine that is highly scriptable via Lua.
raylib - Cross-platform, open-source game development library in C.
MOS - Lightweight game engine.
SDL - Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level...