Board Thread:Questions and Answers/@comment-26569747-20160630231005/@comment-27718903-20160701065605

I've read that the number of possible outcomes has no effect on the odds of getting a Diamond, but through my own research, I've found that breeding Wizard and a Green/Yellow hybrid should have double the chances, since it also had a chance for Infinity (a slightly better version of Diamond). I have yet to fully confirm this though. Take note that you HAVE to use a Wizard Dragon, but the other can be anything as long as it has the Green and Yellow types (but not split from a minor type).

If you're really intent on finding the least amount of outcomes, then from what I've found, Stone x Candy Cane seems to have the least amount of outcomes possible, I think 13 including Diamond.