I'll throw something up the flagpole, albeit not exactly in the form the OP asked for:
25-man:
Betrayer of Humanity from KT,
The Jawbone from Maexxna
10-man:
Death's Bite from KT,
Demise from Heigan
Heroic Dungeons:
Colossal Skull-Clad Cleaver from Loken in HoL,
Saliva Corroded Pike from Moragg in VH
Normal Dungeons:
Ingvar's Monolithic Cleaver from Ingvar the Plunderer in UK is literally the only one worth mentioning
Quests:
De-Raged Waraxe from "The Champion of Anguish" in Zul'drak,
Maker's Edge from "Norgannon's Shell" in Storm Peaks
Rep Rewards:
Runeblade of Demonstrable Power from Ebon Blade,
Argent Skeleton Crusher from Argent Crusade
Auction House:
Titansteel Destroyer crafted,
Saronite Mindcrusher crafted
My current spreadsheet says that the 25-man top 3 are Betrayer of Humanity, Death's Bite, and The Jawbone (ignoring, both here and above,
Inevitable Defeat, which is a zone drop and thus cannot be reliably acquired). The 10-man top 3 are Death's Bite, Titansteel Destroyer, and Demise. The pre-raid top 3 are Titansteel Destroyer, Colossal Skull-Clad Cleaver, and Saliva Corroded Pike.
Caveat: A number of these weapons (in particular, Death's Bite) derive a lot of value from +hit - if you're hit-capped from other gear, they return to the pack quite a bit...