Whenever I find good tutorials on Pinterest, I save them here:
Some are on things like colour and rendering, but a lot are anatomy, because it's just one of those things you can always find new things to improve at.
I also recommend the book Drawn to Life (volume 1) by Walt Stanchfield:
It's most useful for somebody who is getting relatively confident with their anatomical drawing and wants to start adding a bit more dynamism, gesture and flow to their poses, and to much over the philosophy of drawing and animation. It's a dense read, since a lot of it is made up of old lecture notes used to train the Disney animators behind the Disney Rennaisance.