My main supplier of parts is Aliexpress, and I also buy a lot from Banggood.
At Aliexpress, I recently discovered a board that will interact with Mach3 and has onboard drivers for larger stepper motors like Nema23.
This board takes 24 Volts, has a USB connection to the PC, an SD card slot and 2 x MPEG/control connectors 15-pin/3-row.
I ordered me 1 of these boards to test it on my CNC mill:
Usb Cnc MDK2 4 Axis TB6560 Stepper motor Controller with Mpg Interface 100Khz Driver Breakout Board
I have this tested with Nema23, 24 Volts and the accompanying firm- and software.
It was quite some puzzling to get the drivers installed and I discovered I had to switch off the Windows 10 security feauture that prevents unsigned drivers to be installed. You can set this off via a procedure which restarts your PC via a series of keyclicks and restart options in the Windows menu. It can all be found on the Internet. After this, the board worked perfect.
I also bought a handwheel set, which has a male 15 pin VGA connector, as does the board. I ended up ordering me a female-to-female 15 pin VGA unit from Ale, will see if this works.
The other 15-pin connector (also male) can be used for simple switches to direct all axes up/down or forward/backwards. I will use this to make auto toggle swtches directly at the machine, next to the Nema steppers. I have some nice jogging handles that will fit perfect for this.
Also, I bought e a 4th axis unit hat will get connected to this boardon the Minimill.
