43 cards where the set is “mat” and the cards are Halo foils

Coppercoat Vanguard (March of the Machine: The Aftermath #186)
Deification (March of the Machine: The Aftermath #187)
Harnessed Snubhorn (March of the Machine: The Aftermath #188)
Metropolis Reformer (March of the Machine: The Aftermath #189)
Tazri, Stalwart Survivor (March of the Machine: The Aftermath #190)
Filter Out (March of the Machine: The Aftermath #191)
Tolarian Contempt (March of the Machine: The Aftermath #192)
Training Grounds (March of the Machine: The Aftermath #193)
Vesuvan Drifter (March of the Machine: The Aftermath #194)
Ayara's Oathsworn (March of the Machine: The Aftermath #195)
Blot Out (March of the Machine: The Aftermath #196)
Death-Rattle Oni (March of the Machine: The Aftermath #197)
Markov Baron (March of the Machine: The Aftermath #198)
Urborg Scavengers (March of the Machine: The Aftermath #199)
Arni Metalbrow (March of the Machine: The Aftermath #200)
Kolaghan Warmonger (March of the Machine: The Aftermath #201)
Plargg and Nassari (March of the Machine: The Aftermath #202)
Reckless Handling (March of the Machine: The Aftermath #203)
Tranquil Frillback (March of the Machine: The Aftermath #204)
Undercity Upheaval (March of the Machine: The Aftermath #205)
Calix, Guided by Fate (March of the Machine: The Aftermath #206)
Campus Renovation (March of the Machine: The Aftermath #207)
Cosmic Rebirth (March of the Machine: The Aftermath #208)
Danitha, New Benalia's Light (March of the Machine: The Aftermath #209)
Feast of the Victorious Dead (March of the Machine: The Aftermath #210)
Gold-Forged Thopteryx (March of the Machine: The Aftermath #211)
Jirina, Dauntless General (March of the Machine: The Aftermath #212)
The Kenriths' Royal Funeral (March of the Machine: The Aftermath #213)
Kiora, Sovereign of the Deep (March of the Machine: The Aftermath #214)
Nahiri, Forged in Fury (March of the Machine: The Aftermath #215)
Nahiri's Resolve (March of the Machine: The Aftermath #216)
Narset, Enlightened Exile (March of the Machine: The Aftermath #217)
Nashi, Moon's Legacy (March of the Machine: The Aftermath #218)
Niv-Mizzet, Supreme (March of the Machine: The Aftermath #219)
Ob Nixilis, Captive Kingpin (March of the Machine: The Aftermath #220)
Pia Nalaar, Consul of Revival (March of the Machine: The Aftermath #221)
Rebuild the City (March of the Machine: The Aftermath #222)
Rocco, Street Chef (March of the Machine: The Aftermath #223)
Samut, Vizier of Naktamun (March of the Machine: The Aftermath #224)
Sarkhan, Soul Aflame (March of the Machine: The Aftermath #225)
Sigarda, Font of Blessings (March of the Machine: The Aftermath #226)
Tyvar the Bellicose (March of the Machine: The Aftermath #227)
Drannith Ruins (March of the Machine: The Aftermath #228)

The message was clear to Sorin—time to search for something else.