Ice cream van.
A medium van with refrigerated storage that draws battery power. So long as the storage battery is charged, food stored in the van will take significantly longer to go rotten.
Armoured truck.
Usually found in the vicinity of a bank, these large vans have a well-secured freight section which will require skilled lockpick use or smashing with heavy tools to access (or you can simply remove the doors once you find a welder). There’s nothing but worthless money bundles inside, but the whole van is decked out in hard plating, making it a very tough vehicle even without modification.
Forklift Truck
Usually found at Public Works. Small, agile, noisy, not very fast. You can use the “move furniture” construction option to place a crate or other furniture item on the front forks, and the forklift will then carry that item when driving.
Police Car
Usually found near police stations. A standard car but with slightly better plating and engine. Will often contain a small variety of police-related equipment - shotgun, expanding baton, riot helmet, etc. Has a siren and flashing lights which can be activated via vehicle controls, which will draw in zombies from a wide area - great as a distraction or to draw them into a killing zone. May also summon eyebots/copbots?
Ambulance
Usually found outside hospitals, occasionally near doctor’s office. A fairly standard van, but with a small stock of medical items - drugs, first aid and bandages. Has a similar siren-and-lights system to the police car. Also usually carries a gurney. A gurney is a bulky inventory item which can be Activated and deployed on an adjacent square. It then becomes a dragable item like the carts added in the recent updates, capable of carrying a fair volume of items.
Fire Engine
I don’t think there are currently fire stations in the game, so for now these would be found rarely in city streets. A large, long truck, most of its storage is given over to water tanks, which will typically contain a large quantity of water for survivors to salvage. Also a good source of fire extinguishers, gas masks, and of course rubber hoses. Its main sprinkler hoses can be taken - they’re bulky to carry, but can be used in place of 30’ ropes when descending broken stairs. In later game iterations, the ladder could be used to access high windows or rooftops.
Riot Truck
A rare find at police stations and military outposts, this armoured van has almost as much water storage as the fire engine. It uses it to fuel the mounted water cannon, a turret weapon which does low damage but stuns and knocks enemies back several squares at a time.