Any of the other art styles I've covered can be used when painting with Neutrals. The mixes of Hues, contrasting lights and darks, softer blended ranges, etc.
The chart here is a good guide on colour intensity. To create Near-Neutrals, you really do want to go past the "Dull" colours, where the colour really starts to disappear and the grey tone becomes apparent.
|Created with painter from|
Bolder & Chainsword