Darkstalkers – 12 Principles is an article that explains the 12 principles of animation through the pixel animation of Darkstalkers
Acting For Animators is an essential book for animators written by Ed Hooks and is the first book about acting theory that is written specifically for animators
Jonathan Abenhaim has an amazing YouTube channel that covers a load of tips, tricks and tutorials on animation. He posts regularly so make sure to subscribe!
Orca Jobs List is an amazing website for finding jobs in game development and can be filtered to only display specific roles (like animation!)
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.
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.