Who are the characters in "Hamlet" that show deception?
Most obviously is Claudius, who kills his brother the king in order to obtain the kingdom. His deception came in the form of hidden murder, and he attempts to maintain that deception at great lengths. When he suspects Hamlet knows, he has him followed, spied on, ordered his failed murder, then orchestrates the final death scene at the end-all to keep his deception covered.
Then we have everyone who goes along with Claudius' plan. Polonius uses Ophelia in order to glean more information for the king, so Polonius was deceitful. Ophelia herself, through simple passivity (not protesting) was deceitful, because she agrees to speak with Hamlet for the express purpose of being spied upon. Rosencrantz and Guildenstern and deceitful as they help the King gather information about Hamlet, in essence betraying their friendship with Hamlet.
Even Hamlet himself shows deception. He goes about the castle deliberately acting strange, as a way to deceive people into thinking that he is crazy or mad; this helps him to more thoroughly investigate his father's death without raising suspicion. So, pretty much everyone in the play practices some sort of deception, all circling around the initial deception of the king's murder.