373 cards found matching energy cost is at least 4

Oasis Raider
Ocean Drake
Onslaught
Ornn, Blacksmith
Ornn, Forge God
Overt Operation
Pakaa Protector
Peak Guardian
Perched Grimwyrm
Petty Officer
Playful Phantom
Plaza Guardian
Poppy, Defender of the Meek
Poppy, Paragon
Possession
Primal Strength
Prize of Progress
Production Surge
Profiteer
Progress Day
Promising Future
Qiyana, Victorious
Rabadon's Deathcrown
Rage Amplifier