Much simpler takes on the color picker.
If you couldn't tell, the key word here is "range".
If you've ever used Google Maps API you know that it takes some getting used to, especially for front-end devs. gmaps.js takes some of that implementation burden off you.
This library reminds me of Upstatement, a web agency here in Boston whose niche is digital publications, and this type of utility is one I'm sure they think about with new projects, because it's an advanced dive into typography via CSS.