Bone/Beige/Tan

Conqueror's Siegebreaker Helmet
Source: Vendor
Conqueror's Siegebreaker Greathelm
Prideful Gladiator's Plate Helm (Elite)
Source: Vendor
Grievous Gladiator's Plate Helm
Prideful Gladiator's Plate Helm (Alliance)
Source: Vendor
Grievous Gladiator's Plate Helm
Ruthless Gladiator's Dreadplate Helm (Elite)
Source: Vendor
Vicious Gladiator's Dreadplate Helm
Source: Vendor
Bloodthirsty Gladiator's Dreadplate Helm
Source: Vendor
Vicious Gladiator's Dreadplate Helm, Death March
Deathlord's Helm
Source: Quest
Greathelm of the Warchief (Normal)
Source: Siege of Orgrimmar
Greathelm of the Warchief, Thranok's Shattering Helm, Thranok's Shattering Helm
Greathelm of the Warchief (LFR)
Source: Siege of Orgrimmar
Thranok's Shattering Helm
Valorous Aegis Headpiece
Source: Vendor
Valorous Aegis Helm, Valorous Aegis Faceguard
Skeleton Lord's Cranium
Source: Pit of Saron
Greathelm of the Silver Hand
Source: Halls of Reflection
Second Helm of the Executioner
Soulspun Casque (Heroic)
Source: Atal'Dazar
Greathelm of the Putrid Path
Helm of Burning Righteousness
Source: Sunwell Plateau
Helm of Uther's Resolve