For data tags we have totaly 11 colar:
Odoo16 /odoo/addons/web/static/src/legacy/xml/base.xml line 1121
# data-color="1" title="Red"
# data-color="2" title="Orange"
# data-color="3" title="Yellow"
# data-color="4" title="Light blue"
# data-color="5" title="Dark purple"
# data-color="6" title="Salmon pink"
# data-color="7" title="Medium blue"
# data-color="8" title="Dark blue"
# data-color="9" title="Fushia"
# data-color="10" title="Green"
# data-color="11" title="Purple"

In v14:

- None: 0
- Red: 1
- Orange: 2
- Yellow: 3
- Blue: 4
- Dark Purple: 5
- ... colors in the are placed in order

It's even easier to check if you add the field `` in the kanban view.