Variants

For most (vanilla) versus players, Random tends to be pretty hard to play for survivors. There are hardly any tier-2 weapons around and they have a lot less ammo; there are few medkits and they are less effective; spawns are fast. Most special events offer challenges rather than benefits for survivors.

RandEasy makes things a little more survivable for less seasoned versus players. There are more tier-2 weapons and ammo and a number of other things are closer to vanilla gameplay. Try this if you find Random too challenging to be enjoyable for you.

For most competitive players, I'm willing to bet, Random may be too easy on the survivor side, however. Some might be annoyed at the presence of tier-2 weapons and medkits, even though they are nerfed. Or maybe you've been playing Calamity for so long that you got accustomed to survivors not making it past 50% of any map.

RandHard is there to make things harder and slightly more like popular competitive configs out there. There are (by default) no tier-2 weapons, a a lot less health items and fewer item spawns overall. Tanks spawn more often, too. If you find that Random is too easy for survivors, this is the variant to try.

Random is pretty mild on the randomness; there are many checks and balances in place in an attempt to keep the game very much within the bounds of playability. Randumb is basically what Random would have been without any balancing.

In this variant, tanks can spawn miles away from eachother. Item spawns, special events and witches are different for teams even within the same round.
Probably not to be recommended for anyone.

Then again, if you're up for some real insanity...

If you think Random is overdone with all its silliness, then maybe Random Basic is for you. It has randomized items but almost nothing else. It does not have special events, gifts, double tanks and multiwitches or gnome bonus scoring. It's pretty boring, but it allows you to play Left 4 Dead 2 with random items without going Full Random.