ProRigs are Maya rigs developed by talented artists from animation studios such as Disney, Dreamworks, Pixar and Sony. Available on a subscription model which gets you access to over 40 rigs.
Alien FPS Rig is a free first person rig for Maya based on a sci-fi theme (inspired by Alien). Made by Guillermo Moreno Alfaro.
BOTW Zelda Rig is a free Maya rig based on the Breath Of The Wild version of Zelda. Made by Christoph Schoch.
The Zelda Rig is a free Maya rig made by Christoph Schoch and is available on his Gumroad page
The Link Rig is a free Maya rig made by Christoph Schoch and is available on his Gumroad page
MocapX is a Facial motion capture app for the iPhone that streams the mocap data to Maya in real-time