In Destiny, there are quite a few redemption codes that you can use on the Bungie redemption page to get some unlockable bonus items & collectibles.
Visit the redemption site, register an account and login, then enter the following codes for the corresponding item.
Once you redeem the code, you can retrieve the item from the Special Orders Vendor in The Tower.
Unlockable Grimoire Cards
Class: Hunter – MVD-4N3-NKH
Class: Titan – 3DA-P4X-F6A
Class: Warlock – YKA-RJG-MH9
Destination: Cosmodrome – HDX-ALM-V4K
Destination: Shattered Coast, Venus – 6A7-7NP-3X7
Destination: The Ocean of Storms, Moon – JMR-LFN-4A3
Destination: The Tower – 69P-KRM-JJA
Destination: Valley of Kings, Mars – 69R-DDD-FCP
Enemy: Cabal – 69X-DJN-74V
Enemy: Hive – 473-MXR-3X9
Enemy: The Fallen – 69R-F99-AXG
Exotic: Gjallarhorn – HC3-H44-DKC
Exotic: Red Death – 69R-VL7-J6A
Exotic: The Last Word – 69P-VCH-337
Fallen: Riksis, Devil Archon – TCN-HCD-TGY
Hive: Ogre – 69R-CKD-X7L
Vex: Minotaur – 6A9-DTG-YGN
Unlockable Emblems
Ab Aeterno – JDT-NLC-JKM
Binding Focus – FJ9-LAM-67F
Field of Light – JNX-DMH-XLA
Illusion of Light – JD7-4CM-HJG
Lone Focus, Jagged Edge – 7CP-94V-LFP
Sign of the Finite – 7F9-767-F74
Unlockable Shaders
Double Banshee – 7MM-VDP-MHP
Oracle 99 – RXC-9XJ-4MH
