Elaina, Emissary of Growth

Whenever a creature enters the battlefield under
your control, put a +1/+1 counter on it.
Whenever a creature you control dies, reveal the
top X cards of your library, where X is the
number of +1/+1 counters on it. You may put
up to one card with converted mana cost less
than or equal to the creature's power into your
hand, then put the remaining cards on the
bottom of your library in a random order.