20 cards where (the full Oracle text includes “enters” or the full Oracle text includes “leaves” or the full Oracle text includes “graveyard”) and the color identity ≤ RW and the full Oracle text includes “whenever an artifact”

Assaultron Dominator (Fallout #54)
Battered Golem (Fifth Dawn #106)
Charismatic Conqueror (The Lost Caverns of Ixalan Commander #70)
Confusion in the Ranks (Mirrodin #87)
Daretti, Scrap Savant (Commander Masters #213)
Grinding Station (Fifth Dawn #127)
Hedron Detonator (March of the Machine Commander #31)
Krenko, Baron of Tin Street (Murders at Karlov Manor #135)
Leonin Elder (Mirrodin #10)
Pain Distributor (March of the Machine Commander #33)
Phalanx Vanguard (The Brothers' War #19)
Quicksmith Genius (Commander 2021 #178)
Reckless Fireweaver (Kaladesh #126)
Salivating Gremlins (Double Masters #143)
Sardian Avenger (The Brothers' War Commander #23)
Scrapheap (Urza's Legacy #132)
Summoning Station (Fifth Dawn #158)
Tablet of Epityr (Masters Edition IV #230)
Thopter Architect (The Brothers' War #29)
Urza's Miter (Masters Edition IV #237)

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