These sites I find really helpful.
Some reference images like these are useful if you’re unable to find/join a life drawing class. Though I would highly recommend going to one:
Eadweard Muybridge photography is very helpful in understanding the body in movement.
Just some references, add your own
I removed the last post because it turns out the downloads of those “how to draw” books weren’t legally free. :\ However, here are some other drawing tutorial references and resources that I found on my dash that people might be interested in! :)