With the recent update, Legacy reward pillars have replaced the black chests in all Dungeons. A legacy reward pillar can have a weapon/armor/spell of epic, unique or rare quality.


Dark Dungeons:

Ruined Cliffs - The Battlements - Darkstone Mausoleum (1 Floor)
Ghostfang Wildlands - Heart of Kul - Well of Cinders (2 Floors)
Arkan Moores - Gor Loch - Shadowrock Tomb (2 Floors)
Valley of the Dead - Skull Pit - Pain's Embrace (3 Floors)


Void Dungeons:

Ruined Cliffs - The Battlements -- Puzzling Path (1 Floor)
Ghostfang Wildlands - Shadow Glen -- Time's Doom (2 Floors)
Arkan Moores - Well of Gloom -- Cave of Betrayal (2 Floors)
Valley of the Dead - Temple Gates -- Eternity Vault (3 Floors)


Light Dungeons:

Ruined Cliffs - The Battlements - Whiterock Chamber (1 Floor)
Ghostfang Wildlands - Wisp Grove - Whitestone Gardens (2 Floors)
Arkan Moores - Lost Marsh - Illuminated Path (2 Floors)
Valley of the Dead - Skull Pit - Crucible of Law (3 Floors)


Non-aligment:

Ghostfang Wild - Sullan Hollow - The Underguerns (3 Floors)
Ruined Cliffs - Grayfane - The Gray Tomb (2 Floors) - Legacy
Ghostfang Wildlands - Heart of kul - Roots of the Primordial (3 Floors)
Arkan Moores - Lost Marsh - Shadow of Rel (3 Floors)
Arkan Moores - Gor Loch - Storerooms (3 Floors)
Arkan Moores - Tower of the Broken Souls - Tower Chambers (2 Floors)
Valley of the Dead - Tomb of Kings - Crypt of the High Priest (1 Floor)
Valley of the Dead - Tomb of Kings - Tomb Gatehouse (1 Floor)

Black Chests:

These chests can be looted once per day.

Mount Crimhorn - Hand of Kul, on top of the hill
Ruined Cliffs - Grayfane - Middle of the map


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The maps might not always have the amount of floors mentioned. It should be noted that it's a good idea to open any other chests you find on your way to make this even more profitable... and if you are looking for a certain item, you might want to skip attacking monsters.

Feel free to contribute in the comments below if you find more black chest locations.

Credit to Sean and Daymarr from Signalstudios.net for listing alignment requiring dungeons (sorry, almost forgot to credit.. I wasn't sure If I had to). I didn't mean to take credit for this or use anyone, but just post it here so people know better.

http://www.signalstudios.net/forums/showthread.php?1769-Alignment-Dungeon-Locations