Light’s Justice Level: Requires level 70 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on equip Dropped by: Prince Malchezaar in Karazhan This looks like a total Pally weapon to me.
Anvilmar Hammer Level: Requires level 69 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on equip Dropped by: Outland mobs What is better than a board with a nail through it for a weapon.  This might fall under the weapons that Blizzard considers too silly for transmogrification though.
Filed in: One-Handed Maces
Tremendous Tankard O’ Terror Level: Requires level 85 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on equip Dropped by: Brewfest holiday boss. The new version from the Brewfest holiday boss.  You get one chance per day to win this during Brewfest.  Check the AH if you don’t obtain one.
Filed in: One-Handed Maces
Twilight’s Hammer Level: Requires level 85 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Cho’gall Many healers used this mace during T11 and into T12.
Mace of Apotheosis Level: Requires level 80 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on equip Dropped by: Cataclysm mobs Check the AH for this one.
Filed in: One-Handed Maces
Royal Scepter of Terenas II Level: Requires level 80 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: The Lich King in Icecrown Citadel Drops from Lich King in 25M only.
Gutbuster Level: Requires level 80 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Festergut in Icecrown Citadel Drops in normal 10M only.
Gutbuster Level: Requires level 80 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Festergut in Icecrown Citadel Drops in heroic 10M only.
Sorthalis, Hammer of the Watchers Level: Requires level 80 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: XT-002 Deconstructor in Ulduar Drops in normal 25M only.
Aledar’s Battlestar Level: Requires level 80 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Eadric’s Cache in Trial of the Champion A nice big purple and gold hammer.  15% drop rate.  Drops in heroic mode only.
Totemic Purification Rod Level: Requires level 78 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Sold by: Sairuk & Tanaika A pretty spiky mace.  Requires revered with the Kalu’ak.
Filed in: One-Handed Maces
Unknown Archaeologist’s Hammer Level: Requires level 72 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Azjol-Nerub spiders This is a very low drop from mobs in Azjol-Nerub.  A HUGE hammer on the head of this mace.  Check the AH for this one, or consider selling it if you have one!
Dragonjaw Mauler Level: Requires level 77 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Wrath mobs Check the AH for this one.
Filed in: One-Handed Maces
Gavel of Naaru Blessings Level: Requires level 70 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Sold by: Anwehu & Smith Hauthaa This sells for only 780 justice points from vendors in Shattrath City & Isle of Quel’Danas
Filed in: One-Handed Maces
Swiftsteel Bludgeon Level: Requires level 70 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Black Temple trash mobs This will take some grinding since it is a rare drop off trash mobs but is also BOP.
Hammer of Atonement Level: Requires level 70 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Kaz’rogal in Hyjal Sunnit A great purple glowing mace.  17% drop rate.
Cudgel of Consecration Level: Requires level 70 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Kael’thas Sunstrider in Magisters’ Terrace This icy glowing mace has a 25% drop rate.  Drops in heroic mode only.
Shockwave Truncheon Level: Requires level 70 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Murmur in Shadow Labyrinth This mace has bubbles repeatedly moving off the head of the mace.
Coilfang Hammer of Renewal Level: Requires level 62 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Rokmar the Crackler in The Slave Pens A nice looking mace with a bubble glow effect.
Sand Polished Hammer Level: Requires level 60 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Ossirian the Unscarred in Ruins of Ahn’Qiraj A purple and bronze mace.  It has a 7% drop rate so might take some farming.
Stinger of Ayamiss Level: Requires level 60 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Ayamiss the Hunter in Ruins of Ahn’Qiraj A sparkly silver glow around the head of this silver mace.
Aurastone Hammer Level: Requires level 60 Armor Level: Epic Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Garr in Molten Core A sparkly silver glow around the head of this silver mace.  
Hurley’s Tankard Level: Requires level 51 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Hurley Blackbreath in Blackrock Depths One of the tankard maces, perfect for a Dwarf.
Scepter of the Unholy Level: Requires level 48 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Lord Aurius Rivendare in Stratholme Easy to farm this mace in Stratholme
Runed Mithril Hammer Level: Requires level 44 Armor Level: Uncommon Armor Type: One-handed mace Binding: Binds on equip Crafted by: Blacksmithing A nice and simple looking mace.  Low mats to craft or check the AH.
The Hand of Antu’sul Level: Requires level 44 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Antu’sul in Zul’Farrak This would be so awesome for shamans since it is a totem mace.  Easy to farm.
Wirt’s Third Leg Level: Requires level 40 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Pirate’s Footlocker This is another torch mace, but this one is unlit.
Filed in: One-Handed Maces
Hammer of the Vesper Level: Requires level 35 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: Bosses in Scholomance Dark colored skull is on the head of this mace.  Has a low drop rate off any boss in Scholomance.
Hand of Righteousness Level: Requires level 35 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on pickup Dropped by: High Inquisitor Whitemane in Scarlet Monastery A common mace used when leveling.  Gold and gray with a blue ball in the center.
Excavator’s Brand Level: Requires level 35 Armor Level: Rare Armor Type: One-handed mace Binding: Binds on equip Dropped by: Uldaman trash mobs This mace looks like a torch, but it is a very low drop rate.  Check the AH for this one, otherwise be prepared to grind for it.  Expect this to sell for a bundle in 4.3