Swatches is an iOS app that lets you collect, inspect and share the colors that inspire you in your daily life. If you've ever wanted to paint a wall a true sky blue or color a logo with your favorite flower, Swatches is for you.
Skala Color is a compact and feature-rich macOS color picker that works with a huge variety of formats, covering everything you’re likely to need for web, iOS, Android, and macOS development — Hex, CSS RGBA, CSS HSLA, UIColor, NSColor and more.
Alembic is a Sketch plugin that extracts a color palette from any layer that contains bitmap data. This works for both images and layers with a Pattern fill.
.colors() allows you to paste any code you like to quickly figure out the color palette that's hidden in it. Whether it be CSS, JS, or whatever else. As long as there's a CSS-compatible color in there, the tool will gather it for you.