1-36 of 47 cards where the keywords include Challenger

Affectionate Poro
Bouncer & Bolt
Boxtopus
Braum
Braum
Brutal Hunter
Cithria, Lady of Clouds
Desperate Husk
Fiora
Fiora
Flame Chompers!
Genevieve Elmheart
Jaull Hunters
Jayce
Jayce
Joraal
Kayn
Laurent Chevalier
Laurent Protege
Leona
Leona
Mk0: Windup Shredder
Rhaast
Rimefang Wolf
Rune Squire
Sapling
Savage Reckoner
Screeching Dragon
Silverwing Vanguard
Spider Queen Elise
Stalking Wolf
Swiftwing Flight
Swiftwing Lancer
The Scourge
The Serpent
The Shadow Assassin