Pickup-master zombie. It is chained to a bar, its hands are covered in heavy grease, and it has a stack of notes pinned to its chest with offensive innuendo printed on them. When it sees someone, it will lurch towards them and occasionally a note will fall off, revealing the next one. It inflicts SAN damage and if you ever find them you will unleash a terrible vengeance upon whatever forces conspired to create such a thing.
Door Torso: A dismembered zombie is propped above a door so as to fall if the door is opened.
Zed Vender: A vending machine that contains a zombie ready to be released upon minor or greater damage to the machine.
Ceiling zombie: A whole room actually, with all the furniture glued to the roof and the zombies held to the roof by metal implants in their legs and a large magnet.
Trebuchet: Occasionally a zombie will fall from the sky and explode in close proximity to the player. These can be tracked back to the source, a large wooden contraption and a shipping container filled with tied-up zombies. The nearby N.P.C.s will have an option to ask if they had anything to do with it, and they will reliably have no idea what you are talking about. Killing them still provides a large morale boost though, justice is blind afterall…