slimanimation - to make stick figure or hand drawn animations
Spine - Spine is 2D animation software designed specifically for software and game development.
Brush Ninja - Hand-drawn Animated Gif Creator
Synfig Studio - Just another WordPress site
Pencil2D - Pencil2D is an opensource animation/drawing software for Mac OS X, Windows, and Linux, based on old...
AnimeEffects - AnimeEffects is a 2D keyframe animation tool based on deformation of polygon meshes.