Line of Action is a really useful site for learning about the human form, anatomy, speed drawing and more. Useful for both 3D and traditional animators!
Line of Action
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.
Kristjan Zadziuk – Youtube
Kristjan Zadziuk is an animation director at Ubisoft and has a bunch of great youtube videos that include game animation, motion matching, showreel reviews and more!
Animator's Resource Kit 