Bulls-Eye: Mr. Sikes' little white dog is really a metaphor for his own evil personality.  The dog, with its willingness to harm anyone on Sikes' whim, shows the true evil of the master.  Sikes himself knows that the dog is the symbol of himself and that is why he tries to drown the dog.  He is really trying to run away from who he is.  This is also illustrated when Sikes dies and the dog does immediately also. 

The Jew: Fagin himself is a recurring symbol for the devil.  Several times Dickens refers to him with known devil names or symbols.  He talks of Fagin with flaming red hair and a beard, along with a three-pronged roasting fork, which all are symbols of Lucifer.  Before he is to die, he refuses to pray for himself and his being a Jew has a very evil connotation.  He is greedy and mean trying to pull Oliver and others into his web of evil.

Rose Maylie's Handkerchief: Rose is a symbol of good in this book with her loving nature and perfect beauty.  When she gives Nancy her handkerchief, and when Nancy holds it up as she dies, it shows that by her acts, Nancy has gone over to the "good" side against the thieves.  Her position on the ground is as if she is in prayer, and this shows her godly or good nature.