Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath gets +1/+1 for each unspent green mana you have.

Yeva, Nature's Herald

Flash (You may cast this spell any time you could cast an instant.)
You may cast green creature spells as though they had flash.

Arashi, the Sky Asunder

{X}{G}, {T}: Arashi deals X damage to target creature with flying.
Channel — {X}{G}{G}, Discard this card: It deals X damage to each creature with flying.