19 cards where the color identity ≤ BW and the text includes “whenever a player casts” and the text includes “gain” and the text includes “life”

Angel's Feather (Duel Decks Anthology: Divine vs. Demonic #23)
Apothecary Initiate (Shadowmoor #1)
Auspicious Ancestor (Mirage #3)
Aven Shrine (Odyssey #9)
Crystal Rod (Eighth Edition #295)
Demon's Horn (Duel Decks Anthology: Divine vs. Demonic #57)
Dragon's Claw (Magic 2012 #206)
Golem's Heart (Scars of Mirrodin #161)
Iron Star (Eighth Edition #304)
Ivory Cup (Eighth Edition #305)
Jeweled Torque (Mercadian Masques #301)
Kor Firewalker (Masters 25 #21)
Kraken's Eye (Magic 2012 #211)
Paradise Plume (Commander 2021 #255)
Staff of the Letter Magus (Unstable #159)
Throne of Bone (Eighth Edition #317)
Urza's Chalice (Masters Edition IV #236)
Wooden Sphere (Eighth Edition #321)
Wurm's Tooth (Magic 2012 #223)

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