
Mercurial Geists | Creature | Spirit | Flying
Whenever you cast an instant or sorcery spell, Mercurial Geists gets +3/+0 until end of turn. | Lake Hurwitz

Bloodhall Priest | Creature | Vampire Cleric | Whenever Bloodhall Priest enters the battlefield or attacks, if you have no cards in hand, Bloodhall Priest deals 2 damage to any target.
Madness {1}{B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.) | Mark Winters

Ulrich of the Krallenhorde | Legendary Creature | Human Werewolf | Whenever this creature enters the battlefield or transforms into Ulrich of the Krallenhorde, target creature gets +4/+4 until end of turn.
At the beginning of each upkeep, if no spells were cast last turn, transform Ulrich of the Krallenhorde. | Slawomir Maniak