Quickposes is a tool for art students, illustrators or anyone who wants to focus on improving their drawing skills. By practicing gesture drawing you will not only get better at recognizing certain aspects of poses, but you will also build a visual library of characters and models.
Animator Island is a treasure trove of animation secrets, techniques, tips, and information on your quest to become a Master Animator
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!
Animation Exchange was an 8 hour twitch stream hosted by a bunch of lovely animation veterans. The aim was to take the knowledge sharing and powerful community of art and development conferences and make it accessible to all, and it was awesome!
Alejandro Garcia has a huge Youtube video series all about physics in animation, covering topics like forces, weight shift, jumping and more!
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”
Extra Play focuses on analyzing video game animation and has over 40 videos that do just that! You can also follow Daniel Floyd on Twitter for more goodness.
Howard Wimshurst has a youtube channel filled with some great animation techniques that apply across both 2D and 3D disciplines.
GDC Tricks of the Trade 2017 is another great talk full of industry veterans giving away free animation tips.
Animator's Resource Kit 