Spirit - The animation tool for the web.
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
Pinreel - Pinreel is lightweight application software that is used to create fun and interesting animation videos by using pro-level templates.
Synfig Studio - Just another WordPress site
Adobe Animate - Adobe Animate is a Flash, vector animation software.
Marionette Studio - Marionette Studio is an online animation software for beginners and professionals. Animate 2D characters and environments in minutes with no prior skills.