Neverwhere

The bead that falls off of Anaesthesia’s necklace after the darkness takes her on the bridge symbolizes courage and self-sacrifice, two traits Richard needs to pass the ordeal. Just as he’s about to fail, which would result in his suicide, he touches the bead and is inspired to do whatever he must to succeed. 

A figurine carved out of volcanic rock appears several times in the novel, though its importance isn’t revealed until the characters enter the labyrinth outside of Islington’s prison. Because the figurine is shaped like the Great Beast of London, it will grant the holder safe passage through the labyrinth.

It’s unclear how many of these figurines Islington has, as one was given to Lord Portico and another to Door. The fact that they’re volcanic speaks to the legend of Atlantis, which supposedly sunk into the seas after a tectonic event. Considering Islington caused the destruction, these tokens might be connected to Atlantis.