Additional Cookie Cutter Shapes?

I'm not much on downloading "free" stuff as there's no such thing as free right?  But to your question, yes it's possible to download more shapes on the web.  As an example: http://www.shapes4free.com/

Then an example of how one might install additional shapes into PSE: https://www.youtube.com/watch?v=YDQclNkm0vU

Full disclosure I've never downloaded or installed shapes in PSE but it looks simple enough.  Good luck!