These signets are Secret Lair ones, illustrated by Dan Frazier

Vadrok's Speedy Dash Vadrok, Apex of Thunder | Illustration by Zack Stella Commander (1) Planeswalkers (2) Narset, Parter of Veils Teferi, Time Raveler Creatures (15) Birgi, God of Storytelling Dockside Extortionist Flamekin Herald Glitterfang God-Eternal Oketra Grinning Ignus Kykar, Wind's Fury Mardu Scout Purphoros, God of the Forge Ragavan, Nimble Pilferer Rootha, Mercurial Artist Screamreach Brawler Vega, the Watcher Viashino Sandscout Zurgo Bellstriker Instants (12) Capsize Chaos Warp Counterspell Dovin's Veto Enlightened Tutor Generous Gift Izzet Charm Mystical Tutor Swords to Plowshares Teferi's Protection Thrill of Possibility Winds of Rebuke Sorceries (21) Ancestral Vision Breath of Darigaaz Cathartic Reunion Chart a Course Citywide Bust Council's Judgment Dismantling Wave Faithless Looting Gamble Inevitable Betrayal Jeska's Will Remember the Fallen Sea Gate Restoration See the Truth Sevinne's Reclamation Slaughter the Strong Solve the Equation Thrilling Discovery Tormenting Voice Wheel of Fate Windfall Enchantments (3) Blessed Sanctuary Impact Tremors Shark Typhoon Artifacts (13) Arcane Signet Cloud Key Coalition Relic Commander's Sphere Crystal Shard Fellwar Stone Hazoret's Monument Mind Stone Sol Ring Talisman of Conviction Talisman of Creativity Talisman of Progress Wayfarer's Bauble Lands (33) Arid Mesa Cephalid Coliseum Command Tower Fabled Passage Fiery Islet Flooded Strand Geier Reach Sanitarium Hall of Heliod's Generosity Hallowed Fountain Island x2 Mountain x5 Mystic Sanctuary Plains x4 Prismatic Vista Raugrin Triome Reliquary Tower Sacred Foundry Sanctum of Eternity Scalding Tarn Sea of Clouds Spectator Seating Steam Vents Sulfur Falls Sunbaked Canyon Training Center This deck capitalizes on Vadrok, Apex of Thunders mutate ability paired with creatures that return to your hand at the end of the turn

Depending on context, these cards may be called prison pieces, hate cards/hatebears, sideboard cards, or, in some circles, stax cards after the ancient Smokestack-based deck which popularized not letting the other person play as a strategic archetype
At the beginning of each player's upkeep, that player sacrifices a permanent of their choice for each soot counter on this artifact
Opponents will know what choices opponents earlier in the turn order made, although cards chosen to be discarded this way won't be revealed until they're discarded at the end of the process
On top of the 10/10 flying body that Ureni comes with, you also have a commander with protection from both white and black, the two colors with the most single-target removal in the game