Are there any good ways to manage all the different chargers?
One thing I love about the DeWalt batteries is that they maintained compatibility across a wide range of battery/charger combinations.  I standardized my own collection on them after my last set of power tools died and replacement batteries weren't available.

As for your challenge, many of these chargers should be wall mountable.  We've got a piece of OSB on the site with a dozen chargers and a couple of power strips all mounted which is mounted on the wall above a workbench.  When we didn't have the trailer hooked up to power, the OSB was unscrewed from the wall and the entire charging station moved indoors.  The nice thing about the power strips is that a flip of the switch turns off all the transformers that leach power even when they aren't charging anything.

In a workshop itself, a ceiling mounted extension cord is handy for powering various tools.  And they also have extra long (6 foot long) power strips that have outlets spaced apart that would be perfect for mounting on the wall behind the workbench.