We’ve seen Reservoir combo decks in Standard before, but we haven’t seen any be remotely successful. The rotation of the 0-mana artifacts in Bone Saw and Cathar Shield effectively spelled the end of combo’ing off in Standard, but Dominaria says not so fast.
Aetherflux Reservoir is a storm engine card all on its own. You’re gaining life for every spell you cast, and then you can use the Reservoir’s activated ability to fire off a lethal amount of damage right at your opponent. You need to pay 50 life to use the Reservoir, which means you’re going to need to cast a considerable number of spells to go off. The 8th spell you cast in the turn will mean that you’ve gained 36 life off Reservoir triggers, so this could be enough to win, while the 9th spell gaining you 45 total life is quite likely. The strangest thing about this build to me is that there’s only a single copy of the Reservoir to win with. While you have a single Inventors’ Fair to find it and other ways to dig, this is a little crazy, and you don’t even have Whir of Inventions to help tutor!
One of the cards that benefits this archetype most is in Mox Amber. This is a 0-mana artifact, which is exactly what this deck wants. It’s also a legend and you’re playing very few legendary creatures or planeswalkers in this deck (only 2 in total!). The Mox won’t often produce mana by tapping it as you normally would, but it’s still highly functional.
Mox Amber may not be able to tap naturally, but you have a playset of Inspiring Statuaries to help change that. Giving all of your nonartifact spells improvise means that while Mox may not be tapping for mana the way you would expect, you can still use it.
Your other artifacts also help with your mana production. Prophetic Prism is mostly here for value in a mono-color deck, but drawing a card and then having it sit in play to tap with Statuary before you have a better use for it later is great. Renegade Map provides early mana by finding a land, mid-game mana in conjunction with Statuary, and late game it’s another cheap spell for Reservoir.
Paradoxical Outcome is how this deck goes off. You can play a bunch of artifacts early and then use the Outcome to bounce back effectively everything you have (often not Statuary). By using your artifacts to improvise the Outcome, you only have to spend a single mana to do this. This helps you find more card draw spells and more Outcomes to continue this process. With Reservoir in play, this will end the game.
You also have the full playset of Reverse Engineers to draw extra cards. You can cast this as early as turn 2 to refill and you don’t really mind playing your artifacts even without Reservoir in play since Outcome will be bouncing them later.
Baral’s Expertise is more expensive, even when you can improvise it out, as it has UU in the casting cost, but this can stop your opponent from killing you or bounce three of your own permanents for value. Since you have many ETB triggers, Reservoir, and you even get a “free” spell to cast off the Expertise, this can be a major swing.
Your creature suite is bizarre, but they all work really well in the deck. Baral, Chief of Compliance makes your card draw cheaper while turning your Mox Ambers into Sapphires. Ornithopter is another artifact to use with Statuary for mana or another 0-cost artifact for Outcome and Reservoir. Glint-Nest Crane has a fantastic ETB trigger as you can find your Reservoir, Statuary, 0-mana artifacts, Prisms to draw cards, and many others. Artificer’s Assistant is the strangest card in the deck, but it’s actually pretty sweet here. It’s a 1-mana spell to bounce with Outcome and it allows you to scry through a huge portion of your library since all of your cheap artifacts will give you triggers.
Commit // Memory has a few valuable functions. It can stop your opponent from interacting, and it isn’t even very expensive to do so if you have Baral or Statuary. Memory can make sure that you’re reloaded with cards and also give you outs in case your Reservoir is destroyed, countered, or discarded.
Reservoir Combo decks are always some of the coolest decks to see, especially for a storm lover like me, and this one looks like it has real potential!