Animation Buffet is a great resource for free Rigs and is constantly updated by Jean-Denis Haas (ILM)
Animation Buffet
Tiger Rig (FREE)
The Tiger Rig is a free rig compatible with Maya 2015+
Animstate Forum
Animstate Forum is filled with some amazing industry veterans and also has a lot of other resources across the rest of the website.
12 Principles of Animation
12 Principles of Animation – Alan Becker has made a video series highlighting each of the 12 Principles of Animation as described by Frank Thomas and Ollie Johnston in their book “The Illusion of Life”
Josh Sobel Rigs (FREE+)
Josh Sobel has some great affordable rigs (his Kayla rig is especially great). You can also get his Bonnie rig for free!
Longwinter Rigs ($10/month)
Longwinter Studios are offering access to their whole rig collection (30+) for only $10 a month. Not too shabby!
Animation Mentor
Animation Mentor is an online animation school. The original online animation school taught by professional animators to grow you in the art of character animation.
iAnimate
iAnimate is an online animation school. They offer a complete set of workshops designed to target all animation needs, and put you in direct contact with veteran animators from the biggest & best studios in our industry.
Animschool
Animschool is an online animation school. Animators from the best studios in the world work with students one-on-one, giving the students the best opportunity for growth.
Animator's Resource Kit 