Rapid Rig: Advanced for Auodesk Maya.
*NOTE: Rapid Rig: Advanced is not compatible with Maya LT.
 
RRA is an easy-to-use autorigger with amazing value. RRA can be configured to fit biped models in Maya of any proportions and is feature-rich with functionality like stretchy and cartoony spine, legs and arms, IK/FK matching, space switching, etc.
 
The proxy rig used for initial setup takes all the complicated and tedious work of correct joint orientations and values and naming. Symmetrizing a rig is a breeze, but assymmetrical rigs can be easily built as well.
 
The final rig has a simple UI for doing basic mirroring and selections. For extra power to Maya animators, the add-on Rapid Rig: Poser gives animators even more control and faster iterating.