The Killing

An important clue in the murder of the character Rosie is her keychain.  The keychain is a brass colored metal circle with a bird inside. 

Breaking Bad

WARNING SPOILERS



In the final episode of Breaking Bad there are three keychains.

1.  Walt is trying to steal a car to get back home to New Mexico.  He finds the keys in the visor which makes things easy for him.  The keychain is a white teardrop fob.

2.  To kill his final nemeses Walt creates a automatic gun turret which is turned on by a red remote keychain.  He pushes the button and the gun activates thereby saving himself and Jesse.

3.  Jesse unchains himself with Todd's keys which has a clear plastic bottle opener keychain attached.


So, Keychains saved both of the main characters twice in the final episode of the series.  

Stand Up Guys

Christopher Walken's character Doc writes a note for someone and leaves his keys to his apartment with the note.  His keychain is a plain metal fob.