http://steamcommunity.com/sharedfiles/f ... =121070254
This mod adds a new section to your L4D2 menu with countless mutations and gamemodes. The best part is it only requires subscribing to the one collection instead of all the various mutations separately.
I used this the other day to play Versus Co-Op with 3 other villuns against bots. You could even play versus by yourself against 4 bots with 3 bot specials. We were using it to check out custom maps for versus play. It was nice to go through the campaign and see all the attack locations, ladders, etc.
It has versus modes that allow you to play without tanks which can be a nice way to mix things up.