Keep At Least N Rows maintains the user-specified number of rows in the output. If the first priority input has fewer rows than the threshold, it adds rows from the second priority input until it reaches the minimum.
I built this macro for my reporting use case. I often put it before a Report Table. I want to show as many crucial changes as there are, and if there are fewer than N, I want to show up to N of the unimportant changes.