From season 1 episode 15
From season 1 episode 16
From season 5 episode 14
From season 4 episode 7 The show features many keychains from the motels and hotels the guys stay at.
From season 14 episode 4 Toys are coming to life and trying to kill a comic book shop employee. Sam and Dean figure out a ghost has attached itself to the keychain of the shop. They dispatch the ghost after it inhabits a life size replica of a slasher villain.