Weapons of the Gods had another interest dice set mechanic.
You roll various numbers of d10s depending on skill, and you are looking for sets of the same number. The number in the set is the ten's and the number on the dice is the units, with 0 being 0 not 10.
So 4,4,4,5,8,8 you could either have a result of 34, or 15, or 28.
you only use one set to see if you succeed or not. But the clever bit is the River.
you start with a River of two, which means you can store dice two from previous rolls. How it works is as follows, at the start of the conflict your River is empty, after each skill check, you can first elect to discard any dice in your River, called wash.
next you can float any dice from any double or more sets into your River but that means they can't be used in the skill test.
Finally you can Flow dice you have in your River into your active dice.
This means there are a load of strategies you can use to manage your results.
Lets say you have a 2,5 in your River and you roll 5,5,9,9 and 7.
you might discard the 2 float in a 9 and flow the 5 into your total to get 35 better than 25, as a result and a 9 in your river. 9's are handy to have as an Everyday task has a DC of 18 so, even if you roll terrible you can Flow in a 9 to get 19.
Or you might discard the 2 and 5 and float in both 9's, having 25 now, but a pair of 9 at hand for later.
As your character improves you can get a wider River to store more dice, then do you keep sets in it or mixed dice so at least something is more likely to add to whatever you roll.
so by managing your River you can get Legendary 40+, or Impossible 60+ results.
oh and 0's have special meaning as well, as if the set you use is a 0's set then you can gain good (if you pass the test) or corrupt Joss (if you fail it), that you can use to improve your roll or worsen enemies rolls. Which actually gives you motivation to fail some rolls to store the best dice in the River and earn some corrupt Joss for later.