169 cards found matching energy cost is 3

Right of Conquest
Riven
Royal Entourage
Ruthless Strike
Sanction
Scorchclaw
Sentinel Adept
Serene Ascetic
Shadow
Shadows of the Past
Sharkling
Shen
Shipyard Skulker
Shock Blast
Skyfall of Areion
Sneaky Deckhand
Solari Shieldbearer
Solari Shrine
Solari Sunhawk
Soulspinner
Spiderling
Sprite Call
Stand United
Star-Crossed