eBay offers the most out of print fabric.
fabric manufacturing is a lot like fashion. Lines are run once, sometimes if they find a large demand they may run the line a couple times- they decide how much they think will sell and run that much. Then the next season rolls around and it’s time for the new lines. Basics, solids and blenders may keep being run for a year or more but prints often stop . Some people will buy up large lots of the fabric near the end of the run cycle then offer it through warehouse sales or on eBay. Once in a while a shop will have some that simply didn’t sell in their area.