“Hidden” accessory drawer for the Ender 3 series of 3D printers that fits inside one of the 4040 extrusions on the base; parametric design so what it actually holds is customizable for each user. Included STL has space for 5 MK8 nozzles, 5 microSD cards, and one full-size SD card. FreeCAD file includes a sketch of the profile of a 4040 extrusion, so you can line everything up and make sure your adjustments will fit before you print. There is a spreadsheet included to adjust length, as well as clearances if the drawer is too tight. 

Printed in PLA, 0.2mm layer height, follow recommended settings for whatever filament you're using. Color change at 2mm if you want the faceplate to be a different color than the body of the drawer (see pics).