Wick Editor - The Internet's free and open-source creation toolkit.
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
AnimationMaker - Create animated presentations and export them to a video file, animated gif or HTML based on SVG...
Synfig Studio - Just another WordPress site
Adobe Animate - Adobe Animate is a Flash, vector animation software.
Google Web Designer - Google Web Designer is a free, professional-grade HTML5 authoring tool. Build interactive, animated HTML5 creative, no coding necessary.