The Colormate addon does not ship with any color palette files. Most Image editing software has color palettes included. Krita and Gimp ship with a bunch of color palettes which you can simply import in colormate.

The current four Color Harmony Groups were chosen because I found them the to be most useful. Due to the limited space in the blender sidebar I refrained from adding more. If there are enough request for a specific additional Color Harmony Group I will add it.

You can create your own color palettes with most popular image editing software such as Gimp, Krita, Adobe Photoshop or Adobe Illustrator.

There are also color swatch and color palette sharing websites where you can download popular color harmony palettes. One of those which needs no account to download and provides .ase-files is https://coolors.co/palettes