27 cards where the illustration contains “decay”

Abomination of Llanowar (Commander Legends #265)
Abrupt Decay (World Magic Cup Qualifiers #2016)
Aim for the Head (Innistrad: Double Feature #359)
Artificer's Hex (Magic 2014 #85)
Bladewing's Thrall (Scourge #55)
Cadaverous Bloom (Mirage #258)
Cleaver Skaab (Midnight Hunt Commander #11)
Crypt Creeper (Avacyn Restored #91)
Deglamer (Morningtide #118)
Dralnu's Crusade (Planeshift #104)
Drown in Filth (Dragon's Maze #67)
Endling (Modern Horizons #89)
Fecundity (Ultimate Masters #165)
Gangrenous Zombies (Ice Age #127)
Grafted Identity (Magic Online Promos #93940)
Gravepurge (Dragons of Tarkir #104)
Incremental Blight (Shadowmoor #70)
Lich's Mirror (Shards of Alara #210)
Lotleth Troll (Return to Ravnica #177)
Malignant Growth (Mirage #272)
Overgrown Tomb (Unfinity #284)
Oxidize (Darksteel #79)
Rise from the Grave (DCI Promos #31)
Summon the Pack (Unstable #74)
Undead Minotaur (Magic 2014 #119)
Zombie (Innistrad Tokens #7)
Zombie (Innistrad Tokens #8)

It is the moment of discovery, the triumph of the mind, and the end of these results.