Ogres

Ogres were monstrous and destructive creatures of legend and folklore of Middle-earth, although it cannot be said if they indeed existed.
During the Riddle-game with Gollum, Bilbo Baggins, in his attempt to solve Gollum's fifth riddle, sat thinking of all the horrible names of all the giants and ogres he had ever heard told of in tales.
No ogre is ever mentioned in the annals of the Elder Days and none played any role in the wars and battles. It is entirely possible that they were a mythical race.
It is also possible that Ogre was just another name for the Trolls.
They are stated in to have been based off Half Trolls, suggested to be somewhere between the largest orcs and the smallest trolls. They served in Azog's Army as both shock troops and Troll commanders. One commanded a team of catapult trolls. Several Ogres appear in Dale and two are killed by Bard the Bowman. One of the them, notably, had an abnormally small left arm, while his right arm that held his club was more proportionate to the size of his body.
Azog orders a group of Ogres to destroy the Dwarvish war chariots at the beginning of the battle. The Ogres successfully accomplish their mission, knocking down the machines and killing Dwarves with their maces. Some time later, Azog sends another group of Ogres to bring down the chariot used by Dwalin, Balin, Fili and Kili on their way to Ravenhill. However, the spiked wheels of the chariot behead all the attacking Ogres.