Something I've wanted to make was a data type to represent a value that may or may not be known with a level of certainty over a certain distribution (or probability density function), but you could apply various transforms that may or may not have their own level of uncertainty, and you end up with a refined set of probability distributions each observation (or a new set of classifications based on whatever conditionals).

With the eventual goal of running various simulations over different randomly generated outcomes based on those probability distributions.