I use Dresses from Dharma Trading Company. These are made of soft cotton jersey for girls to have lots of fun in.
The dresses are cut larger to begin with, so these are true sizes after they're tie dyed! These are great quality dresses!
I do recommend washing on the delicate cycle, to preserve them longer... but that is just a suggestion, not a necessity.
Baby dresses are on the Baby Stuff page
These are assorted prices