Spirit - The animation tool for the web.
Spine - Spine is 2D animation software designed specifically for software and game development.
Lottie by Airbnb - Easily add high-quality animation to any native app
Synfig Studio - Just another WordPress site
Haiku Animator - Create powerful animations for any app or website
AnimeEffects - AnimeEffects is a 2D keyframe animation tool based on deformation of polygon meshes.