how to choose a longest list of more than two ones?

Hello guys, first time asking here :)
Got some trouble with repeating an action. I set a number of random values, then perform a lot of things on them, and finally gain a list of values. In this final list i have several numbers.
When setting another value for Seed option in initial Random Component, in the end I gain a list of another length. If I set third number for Seed i gain another final list lenght, etc.
The task is to choose the longest list (not the number of items in the longest list, but list itself). So further i am gonna operate only with this one.

Sorry for a stupidly described problem, i believe there is some pretty simple way to do this...
p.s. the definition is very complex and littered so it's much easier to talk about the essence of the problem in common.