40 cards where the illustration contains “shell”

Artificial Evolution (Onslaught #67)
Benthic Djinn (Mirage #257)
Cabal Shrine (Odyssey #121)
Clue (Shadows over Innistrad Tokens #11)
Clue // Clue (Unstable Tokens #18)
Clue // Clue (Unstable Tokens #18)
Cosi's Trickster (Zendikar #45)
Homarid Warrior (Fallen Empires #22a)
Horned Turtle (Seventh Edition #80)
Jori En, Ruin Diver (Oath of the Gatewatch Promos #155)
Kiora, the Crashing Wave (Born of the Gods #149)
Kiora, the Crashing Wave Emblem (Born of the Gods Tokens #11)
Kraken Hatchling (Zendikar #50)
Macetail Hystrodon (Legions #106)
Merfolk Seastalkers (Zendikar #55)
Merfolk Sovereign (Magic 2010 #62)
Mindswipe (Khans of Tarkir #189)
Mournwhelk (Lorwyn #127)
Mox Sapphire (Vintage Masters #9)
Noyan Dar, Roil Shaper (Battle for Zendikar Promos #216s)
Pearl Medallion (Tempest #300)
Relic Amulet (Zendikar Rising #247)
Retreat to Coralhelm (Secret Lair Drop #407)
Sand Silos (Fallen Empires #101)
Seasinger (Fallen Empires #25)
Shelldock Isle (Lorwyn #272)
Shell of the Last Kappa (Champions of Kamigawa #269)
Shell Shield (Zendikar Rising #79)
Shell Skulkin (Eventide #173)
Shore Up (Dominaria United #64)
Silent Gravestone (Rivals of Ixalan #182)
Spike Jester (Dragon's Maze #106)
Sturdy Hatchling (Eventide #163)
Thallid Shell-Dweller (Time Spiral #226)
Tortoise Formation (Shards of Alara #61)
Trickery Charm (Onslaught #119)
Troll-Horn Cameo (Invasion #316)
Tromokratis (Born of the Gods #55)
Unknown Shores (Theros #229)
Vigor (Lorwyn #240)
Vodalian Zombie (Invasion #286)

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