Ogres

Ogres were a race mentioned only fleetingly once, in The Hobbit.

Overview
Ogres were mentioned in the context of the Riddle Game between Bilbo Baggins and Gollum. After Gollum asked a riddle about what "ruins kingdoms" and "beats tall mountains down", Bilbo tried to think of all the giants and ogres that he had heard of. None of them, however, were destructive enough to meet the description of the riddle.

It is possible that ogres were a mythical monster in Hobbit folklore rather than an actual race. It is also possible that, like Giants and the term fairy, they were simply dropped as Tolkien expanded Middle-earth and the related cosmology (however note that while giants do not appear in LOTR they are mentioned multiple times).

Earlier Legends
In the earlier legends of Middle-earth written before the release of the Hobbit (but which elements of the Hobbit were roughly based on) the ogres were one of the;

The Úvanimor were the monsters, giants, and ogres (and later Wicked dwarves) who were bred from earth by Melko. They feared the feared the sinews of Tulkas arm and his iron-clad fists, when he had cause for wrath. It is said that Túvo protected Men and Elves from them and from ‘evil fays’, and the orcs besides. Among the ogres were the Sarqindi the Cannibal-ogres.

Húrin once fought beside Beren against ogres and Orcs and evil foemen.

Gothmog was a son of Melko and the ogress Fluithuin and his name is Strife-and-hatred, and he was Captain of the Balrogs and lord of Melko’s hosts ere fair Ecthelion slew him at the taking of Gondolin.

Voronwë and Eärendil set sail in Vingilot and were driven south to the dark regions where the fire mountains were. There they encountered Tree-men, Pygmies and the Sarqindi.

It was also rumored that Sauron inducted Ogres into his armies in order to better combat the growing numbers of the West, both in the Second and Third ages. They also appear in the hobbit the battle of the five arms film.

Portrayal in Adaptions
Ogres appear briefly in The Hobbit: The Battle of the Five Armies. They served in Azog's Army as both shock troops and Troll commanders. One commanded a team of catapulter trolls. Two appear in Dale and are both killed by Bard the Bowman.