Fatal Push (): No surprises here, as Fatal Push will likely continue to serve as Standard's premium removal spell for the foreseeable future. The card is especially important to this deck as it provides a way to interact with the creatures that hit the battlefield early. While this is not a deck stacked with Revolt triggers in order to truly abuse the card, there are a number of interactions (mainly through the Deserts included as part of the mana base) that will allow one to squeeze some additional value out of it.
Doomfall (): I've already touched on the value this card provides to the deck under the "Hand Disruption" tab, so I won't go to in depth on it here. However, a three mana way of permanently removing The Scarab God, Hazoret the Fervent, Rekindling Phoenix, and Carnage Tyrant is generally something that deserves a spot or two in similar lists.
Vraska's Contempt (): Currently considered one of the most important removal spells in Standard due to the various Gods and Phoenixes dominating the format, Vraska's Contempt's biggest advantage is how clean the removal is compared to the other answers in the format. It doesn't carry the inherent risk of 's enchantment based removal and doesn't hope that just shuffling a problem card away will remove it from the game (looking at you Struggle). The thing even nukes any problematic Planeswalkers that could otherwise give the deck fits. The incidental lifegain is just the cherry on top of what is already an auto-include for any -based deck. I'm currently only running two in the mainboard due to the additional exile effect already provided by Doomfall, though an argument could be made for a full playset of the card due to its importance.
Phyrexian Scriptures (): Currently testing in place of Bontu's Last Reckoning. I looooooove the possibilities this card provides. Not only does it provide a buff to the relatively underwhelming initial power levels of the creatures in the deck, it also uses that buff to provide the possibility of an asymmetrical wrath in this deck's favor. As if that wasn't enough, it also helps shore up the deck's weakness to graveyard strategies by exiling everything from the opponent's graveyard the turn after the wrath effect comes down. That final ability is huge because its asymmetrical nature hurts the opponent while saving any Dreamstealers waiting in the yard to be eternalized. The real downside with this card is its inability to hit Artifact creatures, something that is exacerbated by the prevalence of creatures like Scrapheap Scrounger and its inability to deal with token strategies. Ultimately this will be a meta call, if Kaladesh block artifacts continue to show up everywhere in Standard then Bontu's Last Reckoning could be the safer choice.
Cast Down (): I'm seriously intrigued by Dominaria's take on Doom Blade. Certain legendary creatures introduced in Dominaria (cough Lyra Dawnbringer cough) will test this card's playability, but it does represent a clean answer to several threats that would otherwise give the deck a hard time. Being able to hit just about any three drop powered out by Llanowar Elves without relying on a revolt trigger or being able to straight up kill a Glorybringer is definitely something I want to be doing.
Ifnir Deadlands (,, Sacrifice a Desert): While this is a land, it deserves an honorable mention as an additional four copies of removal and a valuable protection against mana flooding in the late game. It's worth noting that you could pad this number by sacrificing other deserts that may not provide as much value in certain matchups. The reduction effect is capable of killing smaller aggressive creatures (Adanto Vanguard in particular) while taking the edge off of an opponent's bigger bombs. In my testing so far, the utility this card provides has continued to surprise me and has saved my bacon in some pretty dire scenarios.