Blender Effectors is a free motion graphics addon for Blender.
Patrick W. Crawford writes:
This is an addon project I started to develop at the SIGGRAPH blender booth in Vancouver 2014 to show how easy it is to develop scripts within blender. I wasn't expecting it to turn into an actual addon!
It is a motion-graphics addon inspired by some features I saw in Cinema4D. It turns faces or groups of objects into crowd-animatable (in location, rotation, and scale) entities controlled by a central or multiple armature. It's a simple addon but allows you to do some pretty cool effects quite easily.