Kona Cotton Solids and Moda Bella Solids are both 100% cotton broadcloth...and two of the best quilting solids out there.
Some recent threads on this topic to help ease your mind.
http://www.quiltingboard.com/main-f1...h-t228216.html
http://www.quiltingboard.com/main-f1...h-t225986.html