An Unkindness of Ravens (Actual)
Actually, it's a conspiracy of ravens.
I've heard Unkindness more then Conspiracy, honestly. It fits with the Murder of Crows, though 
I've actually never heard Unkindness before. But I do agree that Conspiracy fits better with Murder!
A Tsunami of Sahuagin
I'm partial to A Tide of Sahuagin myself
I considered that, but I figured sahuagin are more apt to act like a tsunami than the tide when they attack....
