Colors in variables.css

I’m creating some custom themes. While looking through the variables.css file, I see some variable definitions that reference another color definition in their comments. Most of these are never defined as actual variables, which is fine. But what I am seeing is that not all the shades of many colors are listed. What I am wondering, is if there is a full color palette somewhere. For example, there are red-50, red-60, and red-90 but not the rest of the “red” palette in variables.css. A few, like purple, are fully or nearly-fully defined since all their values are used somewhere. I am just wondering if there is a resource somewhere defining the rest of the shades in each color. It’s something we can create, but I’d prefer to use a “standard” as the base.

Thanks

Google’s material design resources (where the material icons come from) has an outline of colors and theming tools: