I just want to mention that the different shrinkage rates of different fabrics actually don't matter when a quilt is closely quilted. This is because the quilting stitches that bind the layers together also prevent fabrics from shrinking overly much. This doesn't apply if quilting lines are far apart (say, 10" ). As long as you like the crinkly look, as I do, use primarily cotton batting (shrinks on average 3%), and quilt lines fairly close together (I usually do 2" but probably up to 4" is okay), then the variability in shrinkage of fabrics won't matter.
The one exception to this may be flannel, if you are combining it with other fabrics, because flannels can shrink an outrageous amount compared to other fabrics. I once saw a quilt that Harriet Hargrave made to prove her point about not prewashing. She made a quilt entirely out of flannels that she did not prewash. She measured the quilt before washing and again after washing. It shrank the amount of the cotton batting (about 3%) but no more than that because the quilting kept the flannels tied to the batting. Washed by themselves, flannels can shrink 10% or even more!