Cayth, Famed Mechanist Commander Deck Tech
Playing Around in Santa's Toyshop
It feels like a gift when you find a commander you had never heard of, especially when it winds up being a remarkable piece of design that does a lot of cool things you like to do. I will admit, with the bounty of commanders we've been blessed with over the last year, I had never heard of Cayth, Famed Mechanist before. Let me tell you, after crafting this monster of a list, I will NEVER forget this amazing Jeskai commander again.
She's a combo player's dream, and one that plays beautifully with absolutely everything the Kaladesh Block was trying to do. I'm not sure she's from Avishkar, but, if she is, she might just be their version of Santa Claus: building toys, fueling fun, and working tirelessly to make the miraculous happen.
Win Conditions
Cayth is an incredible commander, with a huge suite of abilities ripe for combos. To begin with, she has fabricate, which makes her four mana for either a 4/4 or for a 3/3 and a 1/1. As a result, she's already fairly mana-efficient. She also has the activated ability to populate or proliferate, so she works well with both token and counters strategies.
Finally, she grants other nontoken creatures fabricate, so creatures entering the battlefield make a Servo or enter with a counter, making blink and artifact strategies work. There's a wide array of options here, but mixing and matching these abilities can create a Spellbook worth of combos...a Commander's Spellbook!
The combos this deck is capable of range from infinite creatures to infinite energy to infinite mana, and quite a lot in between. Ojer Taq, Deepest Foundation and Anointed Procession allow us to make exponential tokens.
These tokens can fuel various win conditions, like pinging opponents with Goblin Bombardment or, if they share a name (which tokens do), proccing a win with Mechanized Production. Remember: Mechanized Production's win con doesn't care about what it's enchanted on!
Another way we can win is with artifacts coming and going. Artificer Class and Kappa Cannoneer, once fully online, amass counters as artifacts enter. They don't care if the artifacts are tokens or not, so we can use them as exhaust for the countless Servos we're going to be creating. Santa may have scores of elves, but I'll take our army of little robot friends any day, especially a holiday.
While not a hardcore energy deck, we do use energy cards that work alongside our artifact shenanigans. We have some solid uses for the energy stored in our core synergies, such as Whirler Virtuoso making an amount of Thopters limited only by our imaginations... and energy reserves.
Core Synergy
Intruder Alarm is a beautiful combination with our commander, even if we don't have anything else out. For example, Cayth makes a Servo by herself, so every two mana lets us populate the Servo, untapping all creatures and letting us do it again. If we have one of several infinite mana combos going, we can use that to fuel her ability, making infinite Servos. But we don't have to work that hard.
Fabricate cares about creatures entering the battlefield, but it doesn't care about how. A sacrifice outlet allows Karmic Guide and Reveillark to play around in the graveyard over and over, adding Servo bodies as they do their shenanigans. Nim Deathmantle does similarly funny tricks with the graveyard.
What do we do if the graveyard is off-limits? Hullbreaker Horror is a fundamentally broken Magic card, but one area that I haven't seen it used often is its ability to go infinite with Sol Ring. Yes, we do play the most ubiquitous card in the format. No, we're not just using it for fast starts. We have cost-reducers, so there are a number of ways to generate infinite colorless mana, which happens to be what Cayth requires.
Aethergeode Miner might be the single most broken card in this Rube Goldberg machine of infinite combos. The Miner makes two energy on attacking and blinks for two energy. With cards making energy when creatures enter, and the Miner getting fabricate to make a second body when it enters, it can go infinite with a ton of cards in the deck.
Draw
Our draw effects...also go infinite. The Reality Chip lets us cast from the top of our deck, enabling Sensei's Divining Top and a cost-reducer to let us draw our whole library. Myr Retriever and Junk Diver let us get back lost combo pieces, enabling some nutty loops with Krark-Clan Ironworks.
Sphinx of the Revelation, the Sphinx referred to in the titular Sphinx's Revelation from Return to Ravnica, as well as a Sphinx obliquely related to Azor, the Lawbringer, is a broken Magic card. It makes energy when we gain life, feeds that ability with lifelink, and then turns the energy we feed into it into cards drawn. Since we can generate infinite energy a few different ways, we can also draw our whole deck with this guy!
Mana
Most of the mana engines have been alluded to already, with the cost-reducers teaming up with Sensei's Divining Top and the Krark-Clan Ironworks teaming up with the artifact regrowth effects. Cursed Mirror is a bit different, however. It can fill in for a number of pieces, re-use ETB effects, or even go nuts by copying a creature like Felidar Guardian.
While we don't HAVE to make every two cards go infinite, why wouldn't we, if we can? That's the logic behind jamming Dramatic Reversal and Isochron Scepter. They generate infinite mana with any amount of mana rocks, such as Sol Ring. As a result, Sol Ring can check off another combo it's involved in, solidifying its ubiquity in the deck.
The general plan is to mix and match combo pieces, trying to find any of a variety of synergistic infinite combinations. This is a decently high-powered deck, but it is a bit of a glass cannon, as it doesn't maintain a strong board state throughout the early turns. It's also vulnerable to artifact hate and go-wide hate, but it's a blast to put the pieces together and see what happens.
