ID practice.

A few studies from "Sketching: The basics".

Studies.

Some muscle studies from Frederic Delaviers "Strength Training Anatomy" and a few random photo studies.

Studies, continued.

Here are a few more studies from photos (not the vehicles).

The ref for the claw-girl is from quickposes, a very nice site where you can practice figure drawing from a bunch of photos. A function for timed poses is also available.

More studies..

A couple of practice images.