raylib - Cross-platform, open-source game development library in C.
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
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.
Synfig Studio - Just another WordPress site
SDL - Simple DirectMedia Layer is a cross-platform multimedia library designed to provide low level...
Adobe Animate - Adobe Animate is a Flash, vector animation software.