Bilbo's hobbit hole: Bilbo's home becomes a symbol of comfort and warmth for the hobbit. He repeatedly thinks of it throughout his journey in the novel, remembering his home fondly to help him get through the bleak and trying moments of the quest.
Sting: Bilbo's sword, which he names himself, becomes a symbol of Bilbo's courage and determination. The hobbit goes from being unsure of himself and awkward during a confrontation to single-handedly routing multiple huge spiders in Mirkwood to save the dwarves.
The Ring: Bilbo's ring, won from Gollum, becomes a symbol of his cunning and crafty nature. With the ring and its handy power of invisibility, Bilbo becomes a burglar extraordinaire. Despite its wicked potential, Bilbo uses the ring for benign purposes, like rescuing the dwarves from the Elvenking's dungeons and performing reconnaissance on Smaug's lair.
The Arkenstone: Pocketed by Bilbo from the treasure hoard, the Arkenstone, a fabulous gem, represents Thorin's greed, but also his desire to reestablish himself as the King of the Mountain; he feels a genuine connection to his ancestors through the gem and desires it immensely.
The treasure hoard-- Originally belonging to the dwarves and hoarded by Smaug, the enormous treasure pile in the Lonely Mountain comes to represent greed and materialism. As soon as Bard vanquishes Smaug, multiple armies are on the move to collect their 'share' of the treasure. The treasure brings out the worst of Thorin and the dwarves as well, who become increasingly greedy and irrational about keeping it all to themselves.
''The Hobbit'' may be seen to an extent, as the fist proper creative/imaginative manifestation of expression of Tolkien's literary and academic powers.
Tolkien 'used' many background source materials for writing this book, and he himself acknowledged the influence of ''Beowulf'' (old English epic) and old, traditional childhood nuresery rhyme and fairy tales and such sources, also.
For example, some of the major symbols that we see among others, include
* Group of people setting out on a journey or adventure together, a bsic theme or symbol in childrens literature and many old adventure tales or ''gestes''.
* An evil and cunning dragon in a mysterious, mazelike lair (Beowulf type confrontation of evil and fearsome creature in a place of magic and strangeness)
* Stealing of treasure from the dragon, especially a cup or chalice (like Grail legend or fairy tales ) and then fighting and defeating, both like Beowulf and St George (patron saint of England)
* Light/Brightness (outside) and Darkness/Murkiness (inside the lair and undergound where goblins and other evil things etc live)
and so on.
A thorough and detailed textual reading will also yield many similar examples of symbolism borrowed or adapted from some of the old and ancient literary sources of the world.