This simple Sketch 3 plugin will generate a palette of color swatches for you. It doesn't do a whole lot, but it's handy for style guides, and it now works for Sketch version 3.2. This project was developed for the fantastic folks over at Pixel Union.
Just run the plugin, enter comma-separated hex values, hit "OK", and it'll generate a 130 x 130 pixel rectangle filled with that color, a name label for you to change, and both hexadecimal and RGB values along the bottom. Pretty simple.
