327 cards found matching energy cost is at least 4

Whiteflame Protector
Wild Claw
Wildclaw Shaman
Wily Newtfish
Wizened Elder
Wraith of Echoes
Xerath
Yasuo
Yeti Brawler
Yone
Yordle Explorer
Zaunite Bouncer
Zed
Zephyr Sage
Zilean