I made those little containers to organize my screws and nuts drawer. The smallest one is 45mm x 45mm small and the others come in multiples of that: 2x1, 2x2 and 3x1.
Best printed in 0.3mm layer height and 0.5mm line with. That way you only need two solid lines for the outside walls.
They can be connected to each other with a little connector piece.
The author hasn't provided the model origin yet.