Jean-Denis Haas is an Animation Supervisor at ILM and his Youtube channel covers animation tips for beginning animators, acting analysis, animation analysis and more!
Thinking Animation has a great section on the pros and cons of different rigs. As well as a bunch of other resources and tips across the site.
Sketchfab allows you to upload full 3D scenes for others to view directly in their browser. They are the world’s largest platform to publish, share and discover 3D content online and in VR.
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 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 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.
Kinovea is video player that allows you to slow down, study, draw and comment. Primarily made for sports enthusiasts but useful for animators too.
Syncsketch is a really useful free website for posting work and receiving feedback. Just upload a video and allow others to review, draw and make notes.