I've been using these small Sterilite containers for FQs (and scraps that are roughly that size) for years. They're inexpensive, they stack nicely, they're just the right size for a folded FQ, and it's easy to see the fabrics. I've purchased them in many different colors in the past. Sometimes I find these in the household department with other storage items, and sometimes I find them in office supplies.
https://www.walmart.com/ip/Sterilite...Black/17126915
For most of my smaller scraps, I use plastic shoe boxes (shown on the right). I separate by color or style of fabric and tape a label on the front, making it relatively easy to find what I want. The fabrics are stored flat in the boxes, so they don't usually need pressing when I take them out.
I don't even want to count how many shelves I have containing these containers and shoe boxes.
