Dominaria

Marwyn, the Nurturer | Legendary Creature | Elf Druid | Whenever another Elf enters the battlefield under your control, put a +1/+1 counter on Marwyn, the Nurturer. {T}: Add an amount of {G} equal to Marwyn's power. | Chris Rahn

Steel Leaf Champion | Creature | Elf Knight | Steel Leaf Champion can't be blocked by creatures with power 2 or less. | Chris Rahn

Sylvan Awakening | Sorcery | | Until your next turn, all lands you control become 2/2 Elemental creatures with reach, indestructible, and haste. They're still lands. | Adam Paquette