Saheeli Rai plus Felidar Guardian is one of the most obvious combos that exists at the outset of the Pioneer format. Let's take a look at the 60 cards we can put together to support the infinite combo. In this article, we'll focus on a four color version that includes green for ramp and combo consistency, but it is also possible to build it as more of a Jeskai control deck.
4c Saheeli CopyCat Decklist (Pioneer)
4 Felidar Guardian 4 Saheeli Rai 4 Teferi, Time Raveler 4 Oko, Thief of Crowns 4 Once Upon a Time 4 Oath of Nissa 4 Gilded Goose 4 Sylvan Caryatid 2 Arboreal Grazer 2 Elvish Mystic 4 Botanical Sanctum 4 Breeding Pool 4 Temple Garden 2 Mana Confluence 4 Hallowed Fountain 2 Hinterland Harbor 2 Sunpetal Grove 2 Forest (347)
Let's start with the obvious: Felidar Guardian plus Saheeli Rai is how this deck wins the game. Saheeli herself is mostly just a combo piece, as she does not provide a ton of value outside of copying the cat a million times. Felidar Guardian can actually be quite useful on its own, letting us reset any of our permanents that dig through our deck.
Teferi, Time Raveler is insanely good in this deck. Its passive ability to simply turn off any opposing interaction is exactly what this deck wants. One of the hardest parts of playing this deck when it was in Standard was deciding when to go for the combo into an opponent's open mana. It's also a great card to pair with Felidar Guardian, doing a great Reflector Mage impression while also digging deeper for Saheeli.
Oath of Nissa is actually one of the primary reasons to play green, as it is the most efficient card that can dig for either half of the combo. It pairs well with both Felidar Guardian and Teferi, letting us dig very deep through our deck. It also fixes our mana for the numerous planeswalkers, letting us play a mostly straightforward Bant manabase and still being able to cast Saheeli Rai.
Gilded Goose is the only 1-drop mana accelerant in the format that can produce any color of mana. This deck has too many color requirements to be able to rely on Llanowar Elves or Elvish Mystic. Given that we're already going to play Gilded Goose, Oko, Thief of Crowns perfectly supplements the food count and the power level of having three mana available on the second turn. Oko can soak up a ton of our opponent's attention in a wide variety of ways while we take our time assembling the combo that will kill them.
Once Upon a Time is perhaps not as good in this deck as it is in others, but it's still extremely good. It digs us very deep for Felidar Guardian specifically, and can fix our mana or find an accelerant when we miss. It's possible that the existence of this card means that we should be playing some higher impact utility creatures such as Reflector Mage in place of some of the planeswalkers or random ramp creatures.
Speaking of random ramp creatures, Sylvan Caryatid and Arboreal Grazer are the least confident inclusions in the deck. Arboreal Grazer and Elvish Mystic further enable our goal of casting a 3-mana planeswalker on turn 2, as long as our lands cooperate. Sylvan Caryatid fixes our mana perfectly but is quite slow. It will take further playtesting to determine which of these belong and in what quantities.
That's the deck! We're curious to see which version of this combo ends up being better – this four color version that is focused more on the combo or a Jeskai version that just uses the combo as a threat in a control shell.