Valo's Various Pixels

[Gors]

Use purple additive for all colors. Now, saying just that would suffice but I'll explain you the reason of hueshift.

As you are aware already, in pixelart, the "rule of thumb" is to make the darker shades tend to blue or purple, and some even go further by adding yellow tints on lighter shades, like this one found in the green color ramp (the middle one)



Now, there's a reason for that. Usually, we perceive colors based on daylight. This means, usually the main lightsource is the Sun and the ambient is the blue sky. This helps adding yellow and blue hues on highlights and shadows, respectively. Take this pic for example.



The building is white, and the shaded parts are shifted to blue because of the ambient it is in (blue sky). If the sky were differently colored, the hueshift would also be different.

So, now you know the reason of why hueshift tends to blue: because of the ambience. This being said, anything that is in the same ambience should have an equal type of hueshift. Every color ramp should obey to "purple additive" rule.

Let's not forget that while all this should be taken into account before painting your sprites, you're allowed to do tests and try things without fear of "breaking" the rule. After all you should work for pleasant artworks more than anything.