This is a remix of the square tissue box for larger rectangular tissue boxes. To maintain the correct aspect ratio for the blocks, the box is taller than a standard tissue box. There is a model for a riser included as well, which sits under the tissue box to bring it up flush to the hole. It is usable without the riser, but if a tissue does not pull the next one with it, it may be difficult to put bring the next tissue back through the hole without turning the box upside-down, so I recommend using the riser unless you really want to save the plastic.

This was modeled to fit a Puffs brand box. The internal dimensions are 9.25" x 4.85 x 4.5h. With the riser, the internal height is reduced to 3.75". If your box does not fit these dimensions, you should be able to scale all the parts slightly to accommodate your box. The puffs box is open in the front and top as shown in the render. Boxes with a rectangular top slot will show the box cardboard through the top hole, so I have included an additional stl file for a slotted version, which will hide all of the tissue box. I did not print this version, so I do not have a print profile for it, just the stl.

I have included the actual question mark stls and put them in the print profile for convenience. They are just glued into the cutouts sections of the box.