34 cards where the illustration contains “gray-sky”

Adeline, Resplendent Cathar (Innistrad: Double Feature #1)
Ancestral Vision (Time Spiral #48)
Chain Lightning (Amonkhet Invocations #26)
Darkslick Drake (Scars of Mirrodin #30)
Deploy the Gatewatch (Eldritch Moon #20)
Earthlore (Ice Age #231)
Emrakul, the Promised End (Eldritch Moon #6)
Festering Evil (Jumpstart 2022 #119)
Flood (The Dark #27)
Forest (Khans of Tarkir #267)
Forest (Khans of Tarkir #268)
Goldnight Castigator (Shadows over Innistrad #162)
Hall of the Bandit Lord (Champions of Kamigawa #277)
Infernal Scarring (Magic Origins #102)
Ivorytusk Fortress (Khans of Tarkir Promos #179s)
Jeweled Spirit (Prophecy #12)
Knight of the Mists (Visions #36)
Kor Chant (Exodus #9)
Longshot Squad (Khans of Tarkir #140)
Lord of the Undead (Secret Lair Drop #1046)
Mechanized Warfare (The Brothers' War #338)
Memnite (DCI Promos #61)
Plaguecrafter (Jumpstart 2022 #72)
Ral Zarek (Dragon's Maze #94)
Rock Hydra (Limited Edition Alpha #171)
Savai Crystal (Ikoria: Lair of Behemoths #239)
Scion of Glaciers (Khans of Tarkir #53)
Sibling Rivalry (The Brothers' War #152)
Storm Crow (Unstable Tokens #5)
Sylvan Reclamation (Commander 2016 #44)
Third Path Iconoclast (The Brothers' War #223)
Vampire Envoy (Oath of the Gatewatch #92)
Winding Way (Modern Horizons #193)
Woolly Mammoths (Ice Age #278)

Though this query has ended, its relics still slumber in New Argive.