http://quiltingstencils.com/blockdesigns.aspx
Click on either "Blocks" or "Continuous Line Blocks" and you can see a bunch of quilting stencils that should work with the blocks you're making.
You can usually find some quilting stencils at Hancock's or Joann Fabrics, maybe at Hobby Lobby too? Local quilt shops will probably have some.
And there are a lot on eBay, but finding them in the larger sizes might be difficult:
http://shop.ebay.com/?_from=R40&_trk...All-Categories