None of the vanities in my home have drawers to store anything, and they're also fairly small so there's not much space on top. So I did up this simple shelf to screw to the side of the vanity to add a bit of quick and easy storage space. 

Dimensions are 5in tall, 7in wide, 6in deep. (127x127.4x177.8mm). I printed in PETG with 0.48mm layers and it's incredibly sturdy. It's not the fanciest thing, but it's functional. :)