$color-alpha
$color-beta
$color-gamma
$color-psi
$color-omega
Most of the time there'll be dark and light variants of each color, in that case we can apply a --dark or --light modifiers. e.g:
$color-alpha
$color-alpha--dark
$color-alpha--light
In case there are more than one light or dark variants a number system can be applied, for example:
$color-alpha
$color-alpha--dark-1
$color-alpha--dark-2
//...
$color-alpha--dark-n
$color-alpha--light-1
$color-alpha--light-2
//...
$color-alpha--dark-n
dark-1 & light-1 being closest to the main color.
$color-primary
$color-secondary
$color-accent
$color-semantic
$color-neutral
As mentioned in the first seggestion we can apply --dark and --light variants to each color and in case we have multiple variants we can use a numbering system, except for Semantic Colors & Neutral Colors.
Semantic colors should be described semantically:
$color-semantic--success
$color-semantic--error
$color-semantic--warning
$color-semantic--info
These colors are usually made for text and/over background. To do that, Material design has a good hack. Instead of defining specific code for black or grey, they use the opacity of black to apply typography value. In other words, no need to define grey color code, they adjust the opacity of black to 54% or 81% or so. Pretty smart, huh? — Anna Molly - Basic UI color guide
For neutral colors, since they are usually White, black or gray schemes, we can apply a numbering system "similar" to Material Design's color system, with 1 given to the lightest color in the neutral set:
$color-neutral--1
$color-neutral--2
//...
$color-neutral--n