Hello MtG-ers, 

I've recently had quite a lot of fun building and testing this deck, thus I decided to share it with you to take this archetype a few steps further as a community.

Note that the current choices are focused on the Control archetype and not the ramp-midrange dominated side; the later I personally find repetitive and vanilla flavored to play both with and against due to the lack of major decision making and the minimal interaction between the two players and the board.

Here is a list of my inclusions for Sultai Control and the reasoning behind them:

4x Thought Erasure

Thoughtseize for Standard, with an extra U on its cmc and without the 2 hp loss, excellent to know and slow down the opponent's game plan by picking any non-land card to discard. Equally strong bonus on Surveil 1 gives two reasons to play this card as a playset in the main-deck.

2x Tyrant's Scorn

The majority of the good and playable creatures of the current format are at/or below the 3 cmc threshold; also, after September’s set rotation, the lack of good cheap instant removals is a thing. Against Control, with no access to Teferi, Time Raveler in this decklist we access a handy Bounce spell for Murderous Rider and Hydroid Krasis to recast them.

2x Assassin's Trophy

Anything that writes "destroy target Permanent" in instant speed, and has cmc 2 is amazing to have access to. The downside of the opponent getting a basic land out of it, effectively ramping them up, is the reason to keep these goodies to a minimum number between 2/3-of.

2x Legion's End

Extremely potent anti-aggro spell since the majority of this archetype is using full playsets of their creatures, making it probable that they'll have one extra copy of our initial target in play or in hand to remove. Also, as stated earlier, revealing what's in the opponent's hand is valuable information to enhance our decision making, any time we have access to it. Lastly, it's a strong mass removal for any kind of creature token strategy going wide (e.g. Improbable Alliance).

3x Once Upon a Time

It allows us to keep starting hands with mana on the unfavorable side without a mulligan, greatly mana fixing a tri-color deck early at the cost of 0 and at instant speed. Later it can dig deep by looking the top 5 cards for a creature based answer in the form of our Murderous Rider or Hydroid Krasis. It’s strongly debatable whether or not this card is worthy a 3 or 4-of inclusion; for this list I’ve felt satisfied with a set of 3.

4x Murderous Rider

At the moment, best removal card in Standard; an easy playset for any deck that has access to Black mana production. Planeswalkers got a huge power surge boost with War of the Spark and there are quite a few creatures that need to die fast, in instant speed. Losing 2 life for that effect is a minimal price to pay and won't really matter unless our life total is low - even then it's better to risk a play like that than just get a defeat next turn for certain.

3x Oko, Thief of Crowns

This planeswalker is great for transforming the opponent's creature-bombs into minor 3/3 Elks with no abilities. As control we can deal with these easier, or even later since their abilities are no longer relevant. Providing some life points is also an amazing feature, as well as the sneaky trade in his ultimate. Overall, he performs exceptionally well either by absorbing removals/counters, or slickery staying on board protecting himself and our life total from attacks.

3x Narset, Parter of Veils

Dig fast, turn 3, and dig deep, top 4, for a plethora of non-creature answers; usually she will die in a trade after her first activation but she will have provided us with a choice instead of a random top card, and with a couple of extra life points through absorbing an attack or spell. Against slow tempo strategies the chance to activate a second turn skyrockets; if not answered she will lock down the opponent’s extra card draw and its effects (e.g. nullifying Improbable Alliance).

2x God-Eternal Kefnet

Without access to Red mana for Fires of Invention that is used in most Control lists to power up their mid-tempo turns, and in an environment with cards like Questing Beast, Spawn of Mayhem, Rankle, Master of Pranks, Lava Coil a.o., it’s essential to have a robust midrange card blocker to trade creatures and/or removals. The bird God’s 5 Defense value and recurrence effect are extremely useful against creature and removal packed decklists; play around Oko’s +1 and possible counterspells to get the full effect of its recurrence. It provides a ticking clock with its 4 Attack and Flying if left unchecked and the Reveal ability can collaborate with the majority of our list, but mostly close to the realm of overkilling our opponent – meaning that it will provide bonus when we’ll have already stabilized the board.

2x Ritual of Soot

Not having access to White mana for Kaya's Wrath, Time Wipe or Realm-Cloaked Giant, Ritual makes for the best option to get rid of all the strong creatures of up to 3 cmc (e.g. Lovestruck Beast). Questing Beast cmc and above are unharmed but they get on the board slower and they are prime targets for our Murderous Rider and Thought Erasure. Against control it's mostly a sideboard-away card but it can still be useful if the right conditions are met during a long game 1.

2x Vraska, Golgari Queen

Most 3 cmc permanents are prime targets for removal and Vraska gives us one of the few worthy ways (and easy to access without messing the mana base) to get rid of pesky enchantments, providing an out in case they hit the board before Thought Erasure gets them (e.g. Prison Realm, Improbable Alliance). If Vraska doesn't die immediately after her -3, her +2 ability will make opponents give up resources or attacks to keep her in control so she won't reach the point to -3 again or even Ultimate. Her +2 is perfect to use on extra land draws or Oko's Food token.

3x Hydroid Krasis

Our blocker/attacker/card advantage/life gain Jellyfish Hydra; excellent choise for UG everywhere to invest their mana into. If Oko, Thief of Crowns is nearby, it's worth not hesitating to throw the jellyfish on the board even as an 1/1 blocker, since with his +1 ability Oko will turn it in a 4/4 (the +1/+1 counters stack on every permanent as he transforms it) at the cost of losing Flying and Trample though.

2x Ugin, the Ineffable

Nicol Bolas, Dragon-God’s twin brother is equally powerful as a 6 cmc finisher:

• Produces blockers/attackers.
• Card advantage.
• Removal.

Ugin provides another out on our enchantment-destruction problem if needed since his -3 targets any-colored permanent. Liliana, Dreadhorde General and Garruk, Cursed Huntsman are equally good finishers and they do the same job as Ugin for card and board advantage, a bit differently, while they also synergize well between themselves. Personally, I prefer the dragon planeswalker out of the 3 but 1-of each or any combination of all 3 is viable.

1x Lochmere Serpent

It has a huge body of stats printed on it while instant speed cast with Flash. Also it has recurrence with its last ability, making it a pain for Control. Alongside Vraska, Golgari Queen it can utilize our excess lands by using them as fodder to provide card draw, or get Unblockable to finish the game.

4x Watery Grave – Overgrown Tomb – Breeding Pool

Shock Lands; named after Shock since we need to get the same amount of damage to allow them to enter the battlefield untapped. It’s a worthy sacrifice for any tricolor deck, as we greatly fix our required mana production consistency, as long as we don’t take it too far on self-Shocking; in a worst-case low hp scenario treat them as Gates (e.g. Golgari Guildgate).

2x Fabled Passage

Mana fixer and life point preserver against Aggro: 3 playsets of 12 Shock Lands might hurt a lot against such strategies and it's better to save those couple of life points to reach the Mid-Lategame with land drops coming into play at the right moment untapped if possible. Life points are the most valuable resource for Control against Aggro, since we willingly give up a great portion of them to survive until we reach our endgame turn.

2x Dismal Backwater

Mostly chosen to fill in the need of early-mid Black mana fix as well Blue. Alongside Castle Vantress and Fabled Passage we reach 6 lands that come into play tapped, which is an acceptable number for a tricolor control deck trying to mana-fix. Though Castle Vantress and Fabled Passage count on paper towards that tapped total, their conditions are quite easy to fulfil to benefit of them reliably as untapped lands. For Dismal Backwater especially, providing even 1 life point can make the difference against an all-out aggressive playstyle, until we stabilize and/or reset the board (e.g. Ritual of Soot).

2x Castle Vantress

Excellent choice for all Blue based Control decks: Srcy 2 is an extremely powerful ability to access, especially during the opponent's End Turn step and also against other control matchups that might end up on top-decking.

Sideboard:

2x Veil of Summer

Our mana base tapping into Green is not really friendly for double-green cast requirements up to the 4th turn especially (thus i ommited the Shifting Ceratops from this list: GG cost to cast and G to activate); Veil offers exactly what we need to balance Blue counter-happy or Black target-focused strategies. With the upside of drawing us a card, if played timely it can nullify a powerful effect on one of our permanents or us, which can be game winning.

3x Disdainful Stroke

Cheap, easy to access and a solution to the cmc slot that causes the biggest problems to out decklist. At the moment there are a lot of >4 cmc cards that are powerhouses (e.g. Fires of Invention, Conclave Tribunal, Spawn of Mayhem) and they should be answered preferably before they hit the board.

2x Noxious Grasp

Focusing on the heavy Green meta, these two copies are included mainly for their ability to deal in instant speed with the bulky Questing Beast and its green creature friends and even more importantly Oko, Thief of Crowns and Nissa, Who Shakes the World. Just for those two planeswalkers cards that are broadly played and snowball games, some players have already made the case of including Noxious Grasp in mainboard if the deck has access to Black mana. Targeting White also is a nice touch for cards like Ajani's Pridemate and Teferi, Time Raveler.

2x Legion's End

As mentioned earlier. 2 extra copies help lock down most Aggro strategies or cheap key creatues (e.g. Priest of Forgotten Gods).

3x Lovestruck Beast

Control needs to survive the first turns against Aggro while they are beating down on our life total; Lovestruck Beast becomes a sturdy wall by itself between them and us, while it also provides us with a 1/1 blocker even from turn 1 by playing it for its cheap Adventure cost. As a 5/5 it’s standing there to block everything that can survive through, and it can survive a lot of different attacks with that statline.

2x Tamiyo, Collector of Tales

Mrs. Everyone-forgets-about-the-Passive-effect; I have, you have, everyone has at some point. Amazing as a direct answer to Doom Foretold and Priest of Forgotten Gods strategies and a solid pick against long, grindy Control mirrors. Protect her, and she will find you what you need, eventually.

1x Casualties of War

After stabilizing the board against Aggro and Midrange, Casualties of War can lock the victory on our side, while against Control it can make a huge swing towards it if we are behind. It's a spell with a high impact and a high reward that it only stays behind due to its large cmc; as control though, we should be able to reach the point of casting it in most matchups, if needed. It's an answer to everything possible on the board at the given moment.

Honorable Mentions/Maybeboard:

• Grafdigger's Cage is the best answer to completely nullify Experimental Frenzy, if you have a problem with it that can't be solved with one of the earlier mentioned enchantment destruction and control cards.
• Sorcerous Spyglass deals with planeswalkers and other activated abilities. Keep in mind that dangerous activated abilities are not really a huge deal in Standard right now though, while The Elderspell and Murderous Rider deal with planeswalkers easily.
• Questing Beast, the best Green Creature card of the set: an encyclopedia's worth of abilities and text / Shifting Ceratops, an amazing anti Blue and beatdown bomb; both share a common problem: especially for our control and not beatdown oriented mana base, the double Green in their cast requirement (with Ceratops needing an extra third one to activate his ability) can be hard to acquire on time and consistently. Luckily, Veil of Summer alongside our control goodies can deal with the annoying part of the Blue cards effectively as well as Black ones, while keeping the Green mana requirement to the minimum.
   

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Useful Links for Deckbuilders:

1). https://www.channelfireball.com/articles/how-many-colored-mana-sources-do-you-need-to-consistently-cast-your-spells-a-guilds-of-ravnica-update/

An article on Colored Mana sources and Cast Consistency

2). https://www.channelfireball.com/articles/how-many-lands-do-you-need-to-consistently-hit-your-land-drops/

An article on Land Drop Consistency

3). https://www.channelfireball.com/articles/throne-of-eldraines-castles-are-going-to-be-major-standard-players/

Castle Lands in Mana Base

4). https://cardgamebase.com/mtg-deck-building-guide-tips/

Tips and General Guidelines

5). https://mtgoncurve.com/?v0=eyJjb2RlIjoiIiwib25fdGhlX3BsYXkiOnRydWUsInNlbGVjdGVkX211bGxpZ2FuX2xhbmRzIjpbMCwxLDYsN10sInNlbGVjdGVkX3NjcnlfbGFuZHMiOlswLDEsMl0sIm11bGxpZ2FuX3N0cmF0ZWd5Ijo1LCJpbml0aWFsX2hhbmRfc2l6ZSI6NywiZW5hYmxlX2FyZW5hX2JvMSI6ZmFsc2V9

Calculator of Probability to play cards on Curve