Here are some pictures that I found on the Internet that I want to practice drawing. I find it a lot easier for me to copy elements of a drawing (hand shape, trees, figures, etc.) than to visualize it in my own head. I'm not very good at seeing a picture in my head. If it's a movie that I'd like to shoot, a story to write, or a song to sing, it comes easily. But if it's a drawing, a sculpture, or something of the like, it helps if I have references.
The website where I found most of these is http://www.peterpracownik.com/index.html.
There are a ton more that I want to play with, but I have to get up the confidence to actually start sketching. I'm horrid at drawing and such, but I want to be good at it.