As far as traps/mines go:
Traps:
Rigged Gun
Cost: 1 Weapon + 1 Scrap
Deployment: 8 AP
Effect: Riggs a weapon(generally a shotgun) to fire when a wire is tripped. Due to the nature of the trap, the weapon has perfect accuracy and +50% critical chance, but can only be used once before needing to be reset by the engineer for 4 AP. The weapon is recovered after battle; the scrap is not.
Battering Trap:
Cost: 5 Scrap
Deployment: 10 AP
Effect: Riggs a heavy object(such as an engine block, large piece of wood or metal, chunk of concrete, etc.) to fall on the target when they trigger the trap. Does 10 damage to that square. Can be reset by the engineer for 6 AP. None of the trap is recovered after battle.
Pitfall Trap
Cost: 2 Scrap
Deployment: 20 AP
Effect: The engineer digs a hole in the ground that is too steep for zombies to escape from, then covers it with a weak sheet of wood or metal. When a zombie steps on it, it collapses, removing the zombie from the battle (effectively killing it). Remains after battle if the map does not change, due to being a hole in the ground.
Mines:
Frag Mine:
Cost: $50 or $10 and 2 Scrap
Deployment: 2 AP; 3 Range
Effect: When detonated, shards of metal fly everywhere, dealing 1 damage in a radius of 2.
Concussive Mine:
Cost: $75
Deployment: 2 AP, 3 Range
Effect: When detonated, a large concussive wave eminates from the device, dealing 1 damage in a radius of 2 and pushing zombies back 1 square. If the zombies can not be pushed back, they take an additional 1 point of damage and lose 2 AP next turn.
Cluster Mine:
Cost: $80 or $20 and 3 Scrap
Deployment: 4 AP, 2 Range
Effect: When detonated, a huge explosion sends fire and debris in all directions. Deals 2 damage in a radius of 3.
S-Mine:
Cost: $130 or $50 and 4 Scrap
Deployment: 4 AP, 1 Range
Effect: When activated, the mine pops out of the earth and explodes in mid-air, dealing 3 damage in a radius of 4.
Arc Mine:
Cost: $150
Deployment: 2 AP, 3 Range
Effect: When activated, the mine sends arcing shards of conductive metal around the area which then discharge a high-amperage shock. Deals 6 damage in a radius of 3.
Hellfire Mine:
Cost: $250 or $100 and 8 Scrap
Deployment: 5 AP, 1 Range
Effect: When activated, the mine creates a tornado of fire that sends burning-hot shards of metal flying great distances. Deals 8 damage in a radius of 2 and 4 damage in a radius of 5
Antimatter Mine:
Cost: $100,000,000,000
Deployment: 10 AP, 1 Range
Effect: When detonated, the mine creates a high-energy explosion rivaling the nuclear energy output of most super-giant stars that instantly destroys everything in the area. Deals 1,000 damage in a radius of 1,500.