I have been a fan of Metalwork Colossus since it was spoiled and have brewed a variety of decks with it as the centerpiece or as role player. Here is my latest take for Hours of Devastation.
Creatures
Metalwork Colossus: The main win-con of the deck. It can come down as early as turn 4-5 and begin putting serious pressure on the opponent.
Glint-Nest Crane: Helps to dig for the Colossi and can attack if needed and blocks fairly well early game. It can also crew the Aethersphere Harvester for better attacks and life-gain.
Foundry Inspector: Has a lot of utility in the deck. It of course makes the Colossi cheaper(and all the other artifacts), but also crews the big vehicles.
Scrap Trawler: This card can crew the big vehicles and has so much value/utility when your artifacts die.
Elder Deep-Fiend: Is a really great and really annoying Magic card. My play group hates it so much it was nearly banned (mostly for being unfun, not unbeatable). It can straight up win the game by tapping down blockers for a big Colossi hit, or it can Time Walk an opponent by tapping down all the lands.
Artifacts
Aethersphere Harvester: It can be crewed by every creature in the deck, it makes the Colossi cheaper, blocks very well and can gain some life, which can be very relevant in the deck when it decides to durdle around.
Cultivator's Caravan: Makes the Colossi 4 cheaper and can bring the beats if needed.
Prophetic Prism: Card draw, mana fixing, and Colossi discounting.
Haunted Cloak: Makes the Colossi cheaper and gives them Haste, Trample and Vigilance which is awesome.
Mirage Mirror: One of the HOD additions. It can create a hasty Colossi, or copy one of your opponents best things. It seems super fun and potentially quite good.
Pacification Array: Helps to Pacify your opponents best creature or can help get an attack through.
Renegade Map: fixes mana early game and can be sacrifice fodder for bringing back a Colossus.
Sunset Pyramid: Another HOU addition that might end up being too slow, but I look at as 3 clue tokens that you can crack at your leisure. It also discounts the Colossi and when it has been Demolished(Flavor text), it can be sacrificed to the Colossus.
Skysovereign, Consul Flagship: Kills a dude when it comes down and can bring the beats when I have crewers.
Servo Schematic: Creates 2 artifacts for improvise and is great sacrifice fodder for the Colossi.
Other Spells
Fatal Push: The best removal in standard.
Metallic Rebuke: Is often a Mana Leak in this deck. It is also very easy to bluff in this deck with all the artifacts and a single untapped blue source.
Unlicensed Disintegration: Great unconditional removal with some burn for good measure.
Lands
Hanweir Battlements: Hasty Colossi
Inventors' Fair: Life gain and fetching Colossi in a pinch.
Sanctum of Ugin: Go get more Colossus(or Deep-Fiend) after casting a Colossus.
