These are probably the handiest things I've ever 3D printed.  The lid holders attach to the inside of our cabinet doors for easy access to the lids for our numerous Pyrex bowls.  Of course you must place them strategically to make sure they don't interfere with the doors closing.  Prior to installing these I spent many occasions on my hands and knees looking for lids in the back of the cabinet.  These things have made ours lives easier!  They hold lids for the standard 2-cup, 1 quart, 1.75 quart and 3 quart bowls.  I actually have another one for an odd sized lid that is thicker, but I think that is not a popular item so I didn't include that model.