Craft is a site that gathers high-quality material from films, graphic novels and other visual media and lets you explore how other professionals crafted it. Giving you access to source files from animators and artists. Free Trial is available.
Splatfrog is a website with hours of lecture/demo videos by veteran animator, Ken Fountain. It has both free and paid videos.
The Smearframe Slack channel is an animation chat group where you can talk about anything from inspiration, tips, rigs and more. Get an invite from the link above and join the fun!
Animator's Resource Kit 