The 3D models can be used to make molds with which you can make concrete or plastic brackets, and with a CNC routing machine you can cut them in wood.
The above brackets have been discovered in an old catalog of a company that used to sell wooden doors, windows, furniture... Unlike that time, when such wooden parts were hand-made using scroll saw technique, today they can be made very quickly, and thus mass-produced, if you have access to CNC woodworking machines.
If you are not satisfied with the design of these 12 shelf brackets, please go to page 92 scroll saw shelf bracket patterns where you will find a large number of 2D patterns of scroll saw brackets. We believe that you will find a pattern among them to meet all your criteria.