You have three main options for this project:

1 - Plain knob, flat top, printed up to allow a beautiful flat top with ironing.  Supports recommended for hex nut hole only, but not necessary.

2 - Plain knob, flat top, printed down against the build plate, allows the plate texture to be on the top of the knob.  This configuration does not benefit from supports.

3 - Alphabet knobs, printed up, no AMS required for multicolor printing.  My configuration file uses an AMS, but the text is in it's own layer, so you can easily slice the file with a color swap for multicolor printing on a printer without an AMS / MMU.  Supports recommended for hex nut only, but not necessary.

This is my original model designed in TinkerCAD Codeblocks.  It uses a single M4 nut at the bottom to make it stronger, so there is a single hex shaped support piece that needs to be removed after printing (if you are using my print profile provided).  These models do not necessarily need supports, but the supports painted on the hex nut hole help keep the shape of the hex nut.  The hex nuts press in tightly, so it's highly recommended that you use supports.  I made the hex nut fit tight to help keep your knob on whichever cabinet, closet, etc. you choose to put it on.  

My 3MF file is from Bambu Studio.  This file allows you to print individual parts from each plate for your convenience.  It has the supports and color change already built into it.  It also has ironing built into the upright flat knob.

Why did I make this?  I am not sure.  It just seemed like a fun project to do.  I enjoy the practical side of 3D printing.