I use plastic shoe boxes to put my projects in. I have 2 sizes - one for the larger projects & one for the smaller. Once the tops are done, they are hung over the bannister with their matching backing. I have a special plastic box that holds the binding for each of the tops that are ready to be quilted.
I usually have 4 or 5 projects going at once and only one that has been on-going for over a year (I'm in the avoidance mode
)
I actually have some empty plastic boxes - which just baffles me! I have a few sets of fabric that could go in the boxes, but unless its something I really plan to make into a quilt, I don't put it in a box. The fabric sets were going to be quilts, but then I decided I didn't like them together so they came out to mingle with the other fabric.