btw, I just updated my tools... the colours weren't dynamically in there now black and heart is also in there... I have now a few interesting results. Unfortunately all the "top results" aren't possible.
Interesting is this combination:
Red Heart Blue Black
Left or RightHeart Dragon with Night....
only 5 possible offspring, average weighted failure raite of 4h
Breed two dragons whose colors add up to make 4 colors for example fruitful and charm dragon fruitful dragon is yellow and green and charm is red and purple so all together there are four colours for more information please check the Diamond Dragon page :) hope this helps