Randomizer is a script for After Effects that sequences layers randomly based on an amount that you choose. If you haven't yet, check out the video above for more information on how it works. Randomizer is one of the first scripts I've built and it has save me a ton of time. You have no idea how glad I am to not have to do this repetitive task over and over again. I feel like I do it at least once a project.
This download comes with the script and a user guide.