If you used this tool on GIMP or Photoshop, you know what it is about. It does the same, but the amount of colors can be limited, and you can decide how much dithering it will include.
The gradient will be applied with the primary and secondary colors.
By default, it is limited to 4 colors, and the dithering is set to 60% on the transitions.
Keep in mind: It will be applied on the entire artboard, unless you have something selected, which will then, be limited to that selection.
Unlimited colors? 2? 16? You choose!
How much dithering should be applied? Default is 60%, and 10%~20% is another good range of values for a more retro feel.
A shortcut to change the pattern of the dither.
(This sample had 4 colors and dithering set to 12%)