Ula, Dreams of the Fallen

Flying, vigilance, lifelink
Whenever you gain life, reveal the top card of
your library. If it's a nonland card with mana
value less than the amount of life you gained,
you may cast it without paying its mana cost.
If you don't cast it, put it into your hand.
"There are countless with buried bodies, yet souls not
laid to rest. She is the hope of the forgotten, carrying
their last wishes to fruition."