12 month pajamas from carters

All of the 9-12mo one piece pajamas from carters that I've bought are made in a different material than all the smaller sizes. They are more of a slinky material rather than plain cotton, even though they are called "cotton". I'm assuming it's to make the material more durable with baby crawling, but it seems a little scratchy. Does anyone know where to buy 9-12mo one piece pajamas in plain cotton?