slimanimation - to make stick figure or hand drawn animations
Synfig Studio - Just another WordPress site
Brush Ninja - Hand-drawn Animated Gif Creator
Animation Paper - Animation Paper is a software package for doing 2D animation.
Pencil2D - Pencil2D is an opensource animation/drawing software for Mac OS X, Windows, and Linux, based on old...
CrazyTalk Animator - CrazyTalk Animator, the next level of 2D animation. Create actors using any photo or illustration.