Giants! Unlike some, who thought the giants metaphorical, I have always thought it was pretty clear that JRRT meant real, literal giants. The giants are said to be what drove Beorn (or his ancestors) out of the Misty Mountains, and Gandalf talks about trying to find a "more or less decent giant" to stop up the goblins' second exit so that there will be some safe way to make it through the mountains. Both imply that the giants are real.
The goblins in "The Hobbit" seem to be a full-fledged independent kingdom, not under the control of the Necromancer or anyone else. The Great Goblin is clearly the one who gets to decide what to do with the dwarves (and Bilbo) after they are captured; there is never any mention of the idea of sending them, or even news of them, to any higher up. They seem to know their history; they recognize (and hate) Orcrist, and they hold grudges against dwarves based on past history (unlike the trolls, who simply see them as potential food). The killing of the Great Goblin in this chapter (by Gandalf) does not send them into anarchy; they quickly pick their next leader and start planning their revenge. Altogether, they seem to be a real, complex society, if more than a bit cruel (with slaves to do much of their work, for example).
Those poor ponies. I always thought that Bill the Pony, in LotR, was JRRT trying to make up for the fact that the ponies in "The Hobbit" seem to mostly exist in order to get eaten by goblins and dragons.
Bilbo tried to warn Thorin about the trolls last chapter; this chapter he does manage to warn Gandalf about the goblins in time for Gandalf to kill a few and slip into the tunnels unseen. He's not effective yet, but he's getting closer.
Chapter 5