Animation Methods is a website hosted by animator David Rodriquez and has links to hundreds of rigs, tools and tutorials.
Keith Lango has released his collection of tutorials for free! These were originally made between 2005 & 2010 for paid subcribers only but are now available to everyone.
Rigging Dojo is a website that helps artists overcome the obstacles of computer animation production by focusing on teaching the art and science of character rigging. They have tutorials for both rigging and animation.
I Want to be an Animator is a Youtube collection of free Lessons, Tutorials and Tips about 3D Animation, mostly focusing on the basics and principles.
Jonathan Abenhaim has an amazing YouTube channel that covers a load of tips, tricks and tutorials on animation. He posts regularly so make sure to subscribe!