NOT A LEGO
thingiverse
Out of pure boredom, I modeled something similar to a lego, but almost the same product. Not only did I include the printable file formats, but I also included a detailed and dimensioned drawing interpreted by ASME standards as a pdf in case you want to model and make your own modifications and tolerances. Since it is half a block, you can always make the full block yourself with the given specifications in case you wanted a simple learning challenge :) It is preferable that you print with ABS material, but I've printed in PLA myself.
With this file you will be able to print NOT A LEGO with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on NOT A LEGO.