Your guide is missing the most important one, deadliest in mass PvP: The Goblin Sapper Charge
I think the Goblin Rocket Helmet deserves a mention.
Ice Deflector (Ice Deflector) is also a noteworthy consumable for this list
Although not an engineering item, I would like to know how the Swift Boots Swift Boots stacks up against the engineering speed boots. The Swift boots are made from leatherworking but usable by anyone able to wear leather.