Commotion is an incredible free motion graphics add-on for Blender. It can copy F-Curves from one object to another.

AnimCopy offers these unique features that are particularly useful in character animation:

• Copy the timing and ease of your F-Curves for applying to F-Curves with different values
• Remap the F-Curves to different dimensions (very handy when working with differently-oriented Armature Bones)
• Target just Transform F-Curves (Position, Scale, Rotation)
• Target just the selected F-Curves of the Active Object
• Target just the selected Keyframes of the Active Object

Both are helpful add-ons for your animation work!