I sew my creatures from felt. I brought a large supply of felt from Japan so I'm good to go for a while but eventually I'm going to have to find a supplier in the States somewhere. I've already been looking around for when that time comes but it's not easy.
I've been googling myself silly trying to find craft and fabric stores in San Francisco and Berkeley that sell felt. I found some (a lot less than I thought a large American city would have) and visited them, but was disappointed by the felt. They all only sell eco-fi felt. Even though the idea of recycled felt sounds good, the quality is just too low, especially compared to my Japanese felt. It's not soft and I can actually see through parts of all felt sheets, because it's thin and uneven.
I didn't completely ignore eco-fi felt though, because some of it intrigued me. Like the embossed felt, which is much thicker because of the embossing.
And the patterned felt which has an extra layer of paint on it which hides the see-through spots of the thin eco-fi felt. And some hot pink glitter felt, simply because I love pink and glitters.
Just a little warning for when you find yourself buying these kinds of felt in your local craft store: make sure the bar code sticker is on the non-embossed, non-patterned or non-glitter side of your felt because taking the sticker off (no matter how gently) will ruin the felt right under it.