Not sure where that huge list of collective nouns is and don't have time to look, but.... found this one:
"Though even the most peculiar of the brotherhood of the blade was preferable to the diplomats. He wondered idly what the term of venery might be for a collection of diplomats. If writers formed the brotherhood of the quill, and a group of foxes be termed a skulk ... a stab of diplomats, perhaps? Brothers of the stiletto? No, he decided. Much too direct. An opiate of diplomats, more like. Brotherhood of the boring. Though the ones who were not boring could be dangerous, on occasion."
—Diana Gabaldon, An Echo in the Bone (New York: Delacorte Press, 2009), 12