Llanowar Elves

Melira, Sylvok Outcast

You can't get poison counters.
Creatures you control can't have -1/-1 counters put on them.
Creatures your opponents control lose infect.

Avacyn's Pilgrim

Orzhov Pontiff

Haunt (When this creature dies, exile it haunting target creature.)
When Orzhov Pontiff enters or the creature it haunts dies, choose one —
• Creatures you control get +1/+1 until end of turn.
• Creatures you don't control get -1/-1 until end of turn.

Hidden Herbalists

Revolt — When Hidden Herbalists enters, if a permanent you controlled left the battlefield this turn, add {G}{G}.

Pyre of Heroes

{2}, {T}, Sacrifice a creature: Search your library for a creature card that shares a creature type with the sacrificed creature and has mana value equal to 1 plus that creature's mana value. Put that card onto the battlefield, then shuffle. Activate only as a sorcery.