Heartbeat Sensor - The Heartbeat Sensor was originally going to be in the game, but it was replaced by the MMS.
Datamined icon of the Bipod.
Datamined icon of the Ammo Pack.
Intruder - Most likely fused together for the Access Kit perk.
Lockbreaker - Most likely fused together for the Access Kit perk.
Datamined icon of the Intruder perk.
Datamined icon of the Lockbreaker perk.
Chopper Gunner - The chopper gunner was going to be in the game, but it was cut during development. It behaves like the Call of Duty: Modern Warfare 2 chopper gunner, appears to be the AH-64 Apache. It was replaced by the VTOL Warship.
Race - Appears in game files. Kill the necessary amount of zombies to open your door and progress to the end. First team to make it wins.
Meat - Appears in game files. Grab the meat and throw it. Zombies will only attack you if your side has the meat. Don't die and you might just win.
Datamined image of the Meat gamemode.
Zombie Head - Game files remain. It was a power up exclusive to the Grief gamemode on Mob of the Dead. It's functionality was similar to Zombie Flesh by being a throwable that would attract zombies to tagged players. The head, according to Jason Blundell, belongs to Edward Richtofen.
Datamined icon of the Zombie Head.
Massacre - An unused camouflage with a blotchy red finish, almost resembling blood.