If you have, like me, difficulties to find the right colours and their combinations :( , you'll often visit colour picking sites... or build your own tool :).
Here's a shape that gives you 36 random combinations of colours that you can adjust with controls.
As the text colour should harmonize with the background, it is displayed as well and can also be adjusted.
As colour model, HSL has been chosen as it seems (to me) more natural than RGB.
I hope that this work can be of any use to one of you... enjoy
Yacine