I want a loot plugin where everything is vanilla except barrels, thanks

Can't you use Better Loot and disable all of the other loot containers?

You can use also Loot Plus, or any other loot plugin. Just search for Loot in plugins.

That would make everything else Vanilla right? 

Loot Plus? Yes, not sure about other plugins tho.

How much do you want the barrels to change?  Could be done with just a few lines inside the OnLootSpawn hook.