22 cards where the text includes “deathtouch” and the color identity ≤ RU

Argivian Avenger (The Brothers' War #232)
Atraxa's Skitterfang (Phyrexia: All Will Be One #223)
Basilisk Collar (Commander Legends: Battle for Baldur's Gate #300)
Contortionist Otter Storm (Unfinity Sticker Sheets #15)
Cryptolith Fragment // Aurora of Emrakul (Eldritch Moon #193)
Cryptolith Fragment // Aurora of Emrakul (Eldritch Moon #193)
Crystalline Giant (New Capenna Commander #364)
D00-DL, Caricaturist (Unfinity #187)
Eater of Virtue (Kamigawa: Neon Dynasty #245)
Gorgon Flail (Magic 2010 #211)
Gorgon's Head (Born of the Gods #158)
Hedron Blade (Battle for Zendikar #224)
Hidden Blade (Assassin's Creed #73)
Hunter's Blowgun (The Lost Caverns of Ixalan #255)
Mirror Shield (Theros Beyond Death #234)
Multiclass Baldric (Commander Legends: Battle for Baldur's Gate #684)
Nazgûl Battle-Mace (Tales of Middle-earth Commander #510)
Quietus Spike (New Capenna Commander #377)
Tomb of Annihilation (Adventures in the Forgotten Realms Tokens #22)
Toxic Iguanar (Conflux #72)
Trendy Circus Pirate (Unfinity Sticker Sheets #2)
Vial of Poison (Magic 2014 #226)
Wurmcoil Engine (Double Masters #308)

This search is finished. Now the real work can begin.