Our bathroom has no space to fit a lager cabinet for towels and other stuff. The only spot to put a cabinet is under the sink. Since all off-the-shelf cabinets were to small to fir all of our stuff, I designed a cabinet that makes use of all the available space.
The cabinet was built from cipboard and painted with clear waterproof paint. The drawers were 3D printed from PLA.
A finished 3D printed drawer 
printing the front half of a drawer