373 cards found matching energy cost is at least 4

Raging Firebrand
Raging Soul
Recruit the Vanguard
Red Brambleback
Reinforce
Rek'Sai, Swarm Queen
Rell, Magnetic
Reluctant Leader
Renata Glasc, Industrialist
Renata Glasc, Mastermind
Renekton, Brute
Renekton, Rage Fueled
Rengar, Trophy Hunter
Rengar, Unseen
Revna the Lorekeeper
Rhasa the Sunderer
Rift Herald
Riptide Rex
Rocket Barrage
Royal Guard
Ruined Rex
Ruin Runner
Rumble, Hotheaded
Rumble, Scrapper