Descendant of Kiyomaro

As long as you have more cards in hand than each opponent, Descendant of Kiyomaro gets +1/+2 and has "Whenever this creature deals combat damage, you gain 3 life."

Soul Warden

Whenever another creature enters, you gain 1 life.

Celestial Unicorn

Whenever you gain life, put a +1/+1 counter on Celestial Unicorn.

Survival Cache

You gain 2 life. Then if you have more life than an opponent, draw a card.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)