Combat modifiers for 1/2 dcv in 5e

[g3taso]

I have looked through the rule book and after looking at the combat modifiers table surprise is the only way to get someone at half defense combat value. Am I missing otherwise? Anything else?

[mallet]

In 6th, I can't remember if it is the same in 5th, if the target is prone (laying on the ground) then they are also at 1/2 DCV. 

 

So if you can trip or knockdown your target then that is another way to get them to 1/2 DCV.

[Killer Shrike]

You can put someone to 1/2 DCV or even 0 DCV with a PRE Attack. You can Flash targeting senses which impacts DCV in various ways. You can attack people from behind at 1/2 DCV (though some groups ignore that rule). Entangling, Grabbing, Stunning all affect DCV to 1/2 or 0. 

 

And so on. There's a DCV modifier chart somewhere in the rulebooks and supporting rules text that go thru all of this.