Pinterest is a great place for animation inspiration and reference material. Whether you search for animation, dynamic poses or facial expressions you’ll always find something useful.
Pinterest – Animation
Animator’s Survival Kit
The Animator’s Survival Kit by Richard Williams is an essential book to own whether you’re a beginner or an expert.
Howard Wimshurst Tutorials
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
GDC Tricks of the Trade 2017 is another great talk full of industry veterans giving away free animation tips.
GDC Tricks of the Trade 2016
GDC Tricks of the Trade 2016 has some amazing tips from industry veterans. If you haven’t seen this already you need to watch it right now!
Jason Shum – Videos
Jason Shum is a senior animator at Riot Games and has some awesome free and paid videos on workflow planning, combat, traversal and more!
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!
Artstation
Artstation – Mostly dominated by artists but still a good place for animators to upload their work
Animator's Resource Kit 