Typically, Standard is a format that revolves around Creatures and Planeswalkers. Occasionally, we'll see a super powerful spell like Thoughtseize or Sphinx's Revelation that helps to define the format, but in general, it's all about interacting with permanents. Gabriel Nassif acknowledged this and asked the question: what if you don't have to play Creatures or Planeswalkers to win the game? Typically, this would be a difficult way to approach the game, but Dominaria gave Nassif exactly the tools necessary:

The Mirari Conjecture - Dominaria Standard | Gabriel Nassif

• Instants (19)
• 1 Disallow
• 1 Supreme Will
• 2 Blink of an Eye
• 3 Cast Down
• 4 Fatal Push
• 4 Opt
• 4 Vraska's Contempt

• Sorceries (11)
• 1 Divest
• 1 Doomfall
• 1 Duress
• 2 Divination
• 2 Mastermind's Acquisition
• 2 Secrets of the Golden City
• 2 Yahenni's Expertise

• Enchantments (5)
• 1 Search for Azcanta
• 4 The Mirari Conjecture

• Lands (25)
• 6 Swamp
• 7 Island
• 1 Submerged Boneyard
• 3 Field of Ruin
• 4 Drowned Catacomb
• 4 Fetid Pools

• Sideboard (15)
• 1 Arguel's Blood Fast
• 1 Disallow
• 3 Duress
• 1 Essence Extraction
• 2 Gonti, Lord of Luxury
• 1 Negate
• 1 Reaver Ambush
• 2 Sorcerous Spyglass
• 1 The Scarab God
• 1 Torment of Hailfire
• 1 Yahenni's Expertise

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Outside of The Mirari Conjecture, there's a bunch of obvious choices. Vraska's Contempt and Fatal Push are the core of your removal suite. You get to play a ton of card advantage spells and just a couple of counterspells and discard spells. But once you've ground your opponent into dust by recurring and copying Secrets of the Golden City, how do you actually win?

You can very, very slowly loop The Mirari Conjecture until you can tutor for Torrent of Hailfire out of your sideboard and play it enough times that your opponent runs out of resources.

If you're looking to playing the most controlling deck possible in this Standard format, Gabriel Nassif may well have found it.