What is the best 'TOY, ACTION FIGURE' to use as a Reference Tool(?)
A mirror? I've used GIJoe 12" figures in the past to get an idea of scale to guns (like machine guns and such- handguns are easy, just go to a pawn shop and ask to see some).
A lot of people don't recommend using action figures for ref, mostly because a lot of the proportions aren't quite right, they don't move right, they can't teach you proper bone and muscle placement and so forth.
If you really want to learn how to draw people well, take some life drawing classes. If you don't want to shell out the cash, find some friends or family that will sit still for a few minutes for you to sketch them out.