Colossus decks have been among the most consistent I’ve played. There are so many ways to find your Colossus and to get artifacts and mana into play, that getting multiple 10/10s onto the battlefield by turn 5 is trivial. The problem came when Cat and Marvel would kill you before that mattered, and even Mardu decks ended up being too fast for some 10/10s to matter in time. Throw in the possibility of main-deck Dissenter’s Deliverance and sideboarded Manglehorns, and Colossus wasn’t doing so hot.
The banning of turn-4 combo has opened the door for Metalwork Colossus. Spending 0 mana to make a 10/10 creature is a ridiculously good rate, and having cards like Sanctum of Ugin that can allow you to spend 0 mana to get more 0 mana 10/10s is likewise ridiculous. In many matchups, this would be more than enough to handle taking over the game. You’re often looking at a 1-turn clock with plenty of power in play for blockers. Making sure you can consistently get Colossus into play while staying alive is the challenge.
Glint-Nest Crane helps on all fronts. It’s a reasonably sized blocker that can live to tell the tale. Even when it’s just a chump blocker, you’re talking about gaining a reasonable amount of life from your creature that helps find Colossus or hit your curve.
Elder Deep-Fiend is another possible hit off Sanctum of Ugin that can act as your MVP both offensively and defensively. Tapping down their team or all their mana on a critical turn can keep you alive, and you’ll have a nice-sized Eldrazi left behind. Tapping blockers when you have a bunch of 10/10s in your deck lets you end the game in a single turn.
Adding Herald of Anguish to the deck gives you more potential hits for the early game that your opponents will really struggle to deal with. Herald stays out of range of Fatal Push and Grasp of Darkness, and artifact removal won’t kill the massive flyer. Herald will quickly take over the game, taxing your opponent’s hand while dominating the battlefield.
Cultivator’s Caravan and Hedron Archive are your main mana rocks. Drawing them early should let you play Colossus way ahead of schedule. An Archive and nothing else will still cast a turn-5 Colossus, but you can do even better. Any other artifact being cast in the first few turns means a Caravan and Archive can combine to cast a turn-4 Colossus. Caravan can also be crewed, meaning sorcery speed removal is weaker against Colossus as you can crew it up to block in response.
Metalspinner’s Puzzleknot and Prophetic Prism give you some early plays to fuel Colossus and Herald. Digging through your library while effectively adding mana for both of these huge spells makes them critical components to the deck.
Renegade Map acts as a land in most situations, but can also help accelerate out a Herald earlier when you already have land drops to make. It can be found with Crane, make a Colossus slightly cheaper to cast, and enable revolt in a pinch.
Fatal Push and Kozilek’s Return are your removal spells to stay alive in the early game. You have a number of ways to enable revolt for Fatal Push and kill bigger creatures. Colossus won’t trigger the return on Kozilek’s Return, but Elder Deep-Fiend will. Wiping the board of small creatures either before your 10/10 comes down, or after to clear the way of chump blockers, are both effective plays. A single Battle at the Bridge can act as a huge removal spell with a ton of life gain thanks to this deck’s ability to flood the board with mana and artifacts.
Your final finisher is Skysovereign, Consul Flagship. Taking out creatures and planeswalkers when cast is great, and being able to press that on subsequent turns can put the game away. This is mostly a big removal spell that makes Colossus real cheap to get down (it will often be free the same turn you cast the Ship), and Colossus can somehow jump inside and crew this thing for flying blockers or attackers.
Metalwork Colossus decks shine in metagames that aren’t prepared for them. With everything slightly slowed down, even artifact destruction spells are going to struggle to keep up with the incredible power and consistency this deck offers.