Kinovea is video player that allows you to slow down, study, draw and comment. Primarily made for sports enthusiasts but useful for animators too.
Animation Paper is a popular free software for hand-drawn animation created by Niels Krogh Mortensen
Daz 3D – A 3D morphing, posing, animation and rendering suite, normally retailing at $249 but is now free to download
Pencil 2D – An animation software for vector and bitmap graphics. It is free, multi-platform and open source
Synfig Studio – A free open-source 2D animation software
Blender is a free open source 3D modeling, animation, video editing & compositing software. Like Maya but FREE!