We got a new set of kitchen knives, and the 35 year-old wooden butcher block knife block just didn't fit with our kitchen remodel or the new knives. My wife didn't want anything that would stick out into the workspace on the counter, so what's a maker to do?

Our kitchen is white w. black trim, so black PETG it is (no reason PLA won't work). With some trim highlights of hardware store aluminum, my wife called it "Good".

1/16 x 1/2" hardware store aluminum bar. Cut the aluminum to size, and just press it in.
The block has holes in the back for "ballast", to counter the weight of the knife handles. 1/2" diameter brass bar, cut to length, works well. Or any other heavy metal.
The "Kitchen Knife Block Spacer.3mf" part goes at the tip of the knife in the slot, to keep the knives from pivoting out of the slot. You can change the length and width of that piece in your slicer to fit the knife. Put the knife into the slot, align it with the handle centered in the end, and slide the spacer in at the tip, inset enough so it doesn't show. A drop or two of CA will be enough to hold it in place.

I sanded the surface a bit, and sprayed it with clear lacquer.