fuzzy subnet aggregation

Does anyone have or seen any such tool? I have a script that seems to work, but its terribly slow. Currently I can produce aggregated subnets that can be mising up to a specified number of individual addresses. Which can be fed back in for multiple passes. Doing RTBH on individual /32 does not scale well, if you are eyeing collaboration with external lists. I have found likely sources that could produce another 100k prefixes easily. Joe