EOS and Gorgeous Fabrics are outstanding, I think the latter has the most extensive collection. Fabric Mart is a great source as well, inventory/selection varies. In the past I have gotten some great rayon knit prints and ITY knits from Fashion Fabric Club at incredible prices. Their service is much slower than the others above but always a bargain, I've gotten some stuff I didn't like as well in person colorwise so it was fine for muslins, but quality was still there. Spandex House - in person - is an adventure... I've trolled deep into the dark depths of the aisles pulling out rolls of fabrics not yet displayed and come out covered in lint and threads and had a joyous time - very reasonable - they have an online store with an extensive selection though there is a lot for costuming purposes. Great service as well. I used to have an outstanding semi local source which I hear has changed hands again, I was able to find some amazing textured and print knits that were featured in sewing mags and patterns and even ended up doing some reselling.