Here's a demo of a small facial auto rigger I built in 2017. It was based of the setup I made for Oaken, for the Frozen 24 fps 3D challenge. It's a highly deformable stretchy toon rig. It was designed to be used in productions where large quantities of characters would need to be rigged without having to spend too much time on weight painting. The auto-rig is also modular. This makes it very useful in creating custom facial rigs.