what besides corn startch can i use as a thickener

Arrowroot powder and potato starch work like cornstarch. What are you thickening? There's tapioca flour if you're doing a fruit pie with lots of juices. You can use grated potato as a thickener for soups and stews if not roux based. So many possibilities!

Depends on what you are thickening

Potato starch, beloved of Jacques Pepin.

I agree with pinch&swirl. Arrowroot also puts a nice gloss on the finished product.

Arrowroot is a good thickener as is a roux. http://www.youtube.com/watch?v=qx6tZ8ZU0qc