373 cards found matching energy cost is at least 4

Master Bingwen
Master Yi, Tempered
Master Yi, Unstoppable
Mega-Mech
Megatusk
Mel, Defiant Soul
Mel, Newly Awakened
Minah Swiftfoot
Mindsplitter
Minotaur Reckoner
Miss Fortune, Buccaneer
Miss Fortune, Captain
Monch
Moonlight Affliction
Morgana, Vindictive
Mountain Drake
Mystic Reversal
Nasus, Ascended
Nasus, Guardian of Knowledge
Navori Scout
Needlessly Large Yordle
Nocturne, Horrifying
Noxian Guillotine
Noxus Hopeful