Here are a few pages from watercolour swatch collection showing a variety of greys.
FUB – FRENCH ULTRAMARINE COB – COBALT BLUE CO – COBALT VIOLET BU – BURNT UMBER BS – BURNT SIENNA LR – LIGHT RED CR – CADMIUM RED PS – PYROLL SCARLET CA or AC – ALAZARIN CRIMSON
RMG – ROSE MADDER GENIUNE AU – AUREOLIN RS – RAW SIENNA HYM – HANSA YELLOW MEDIUM HYL -HANSA YELLOW LIGHT NY – NAPLES YELLOW QC – QUINACHRADONE GOLD IN – INDIGO SP -SEPIA
P.Ro – permanent rose
VI -VIRIDIAN CO – CADMIUM ORANGE CLR – CADMIUM LIGHT RED CYP – CADMIUM YELLOW PLAE PG – PAYNES GREY BM – BROWN MADDER NG – NEW GAMBOGE CT – COBALT TURQUOIS