My favorite unbleached parchment paper is by If You Care.

"If You Care Parchment Paper is made from unbleached totally chlorine-free (TCF) greaseproof paper, meaning that no chlorine or chlorine derivatives are dumped into our lakes, rivers, and streams."

I use it instead of aluminum foil for baking and roasting because the toxins and chemicals from bleach and aluminum goes directly in the food you are cooking so this is a great alternative. I also like to wrap cheeses / package foods with it. 

I typically buy it from whole foods but amazon has it as well :)