For the amount of fabric I have, bolts and even foam board would be too thick and take up too much space. For cuts under about a yard and a half I wrap them around comic book boards. They are the perfect size once you give the fabric another lengthwise fold. Then I stack them upright like books on a bookshelf I bought for fabric.
For longer lengths of fabric I ruler fold them (6x24” ruler), and stack them horizontally.
you can buy comic book boards fairly inexpensively, about $10 for 100... Comic book shops sell them, or dealers on EBay.