The prompt this week at Make a Moo or Two is vintage. For the moo cards pictured above, I simply chopped up a bunch of Dover images and layered them onto cardstock. It's nearly impossible for me to make anything without ribbon, so of course I had to use it on two of my cards.
Dover Publications is a great way to collect free images, and many of them are suitable for cards and collage work. You can sign up for their free weekly downloads here.