Our local thrift store offers really great deals on adult clothes. Since they practically give them away, I'll use the mens and womens shirts. Darting is annoying but it's hard to find "pretty" prints on mens shirts.
I also use skirts, dresses, scarves, napkins, place mats, table runners. Anything I can harvest COTTON fabric from, I will. Cause I can get it for next to nothing, its about impossible to pass up. Kids clothes aren't the best for getting alot of fabric, but they often have cute applique or shimmery pockets or ruffled collars etc. All things good for doing doll quits and other crafts.