Over at OneMonk.com they have pages of free paper miniatures for RPGs and wargames
Recently, I took a set of Batman-themed paper miniatures designed by the user Jackmatt, and created PDFs with cutfiles, so they can be cut out automatically with a Silhoutte paper cutter. You could also just do it by hand.
You can find them at http://www.onemonk.com/guest-dl.html, under the name “Gotham’s Heroes and Villains”
The cutfiles I did for Scarecrow’s Stargate minis are there as well.
While you’re there, you might want to check out the Cardboard Warriors forums. They have tons of useful info and advice about creating and using paper minis and scenery.