One metaphor appears in the second stanza of the poem, when the speaker says, of the remnants of a fire in the grate, that "each separate dying ember wrought its ghost upon the floor" (line 8). There are not literal ghosts of embers present, but this choice of words, to indicate that the fire is dying, adds to the spooky and ominous mood created by the opening lines.
Later, the speaker describes his soul as "burning" when he opens the door upon which someone was tapping and sees no one there (31). His soul is not literally on fire, but, to him, it feels as though it is, and so he compares this longing or yearning or curiosity he feels to a fire because the feeling seems to consume him, as fire would. This is another example of a metaphor.
The speaker employs another metaphor when he compares the air around him to air that is "perfumed from an unseen censer" (79). The air seems, to him, to grow denser around him as he considers that he will never see Lenore again, and he compares it to incense-perfumed air that feels as though it has weight.
The speaker uses another metaphor when he compares the raven's appearance to a "kind nepenthe" sent by God to distract the speaker from his grief (83). Nepenthe is a drug that would do away with one's grief or sadness (from Homer's Odyssey); thus, the speaker compares the bird's strange appearance to such a drug.
The speaker employs a simile in his description of the raven's speech. He says that the raven speaks "as if his soul in that one word he did outpour" (56). The speaker suggests that the raven speaks the word "nevermore" with such feeling and significance that it seems as though it comes directly from his soul (though the speaker knows that this cannot be true).