Oh I just had this conversation with my friends group yesterday. Btw while you can, buy brother machines at the going-out-of-business sale! I just got a serger for $270 which is insane! There's EMBROIDERY MACHINES!!! Anyway, here's some more places--my stash of websites is very orientated toward natural fabrics, and historical ones in particular--I'm a rennie.
https://burnleyandtrowbridge.com - SYNTHETIC PLASTIC WHALEBONE FROM GERMANY. BEHAVES LIKE WHALEBONE!!! they also carry clothing, fabric etc but the whalebone is the exciting thing bc I do not know many places in the states to get this stuff.
https://tiedtohistory.com - goldwork supplies and other notions, patterns, some fabric too. Mostly sparklyshinies. This is my source for actual real genuine Thread-of-Gold and Thread-of-silver!
https://angelusdirect.com - Angelus paint, which is a paint used by cosplayers the world over to paint leather and fabric and shoes. It dries flexible and comes in a zillion colours.
https://tandyleather.com - Another leather crafting store, focus more on crafting. They sell tools and machines as well as leather and notions for leather.
https://herrschners.com - string things! Embroidery, latchook, macrame, etc! I hesitate to say a general craft store, but it does have a LOT of stuff. The prices for their DMC embroidery floss are particularly attractive though.
If you have supplies and like them, see if the brand has a website you can buy from direct.
If you need a sewing or serging machine, Bernina is the best, followed by Viking. Brother is best for embroidery machines. Get an older Bernina if you can.
If you live near a fashion city (LA, NYC, Paris, London) then GO TO THE GARMENT DISTRICT. LA has a place you can buy fabric BY THE POUND. It's not got a website it's just a little hole in the wall on like the second floor of a building and a tiny old man is at the counter and has probably been there like a hundred years. NYC has fabric stores that are over a century old. Even my tiny little village has a quilting shop.
Also, join your local historical re-enactors or SCA chapter, that is chock full of crafters looking for new blood. The SCA is a great way to learn crafts you've never heard of, too, like Nalbinding. If you're not careful you'll wake up with an inkle loom and a spindle in your house and like five bags of roving from someone's pet alpaca.
Joann's itself was a corporate takeover of a bunch of smaller local fabric stores, and was sterile and devoid of the REAL kind of community that crafting has. Go look for NON-chain stores, go local! That is where you will find resources--crafters know crafters, because everyone tends to have at least 2+ crafts they do.