Ancestral Tribute

You gain 2 life for each card in your graveyard.
Flashback {9}{W}{W}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Well

You gain 2 life for each creature you control.
Fuse (You may cast one or both halves of this card from your hand.)

Alive

Create a 3/3 green Centaur creature token.
Fuse (You may cast one or both halves of this card from your hand.)

Alive // Well

Archangel's Light

You gain 2 life for each card in your graveyard, then shuffle your graveyard into your library.

Battlefield Promotion

Put a +1/+1 counter on target creature. That creature gains first strike until end of turn. You gain 2 life. (A creature with first strike deals combat damage before creatures without first strike.)

Nykthos Paragon

Whenever you gain life, you may put that many +1/+1 counters on each creature you control. Do this only once each turn.

Benevolent Offering

Choose an opponent. You and that player each create three 1/1 white Spirit creature tokens with flying.
Choose an opponent. You gain 2 life for each creature you control and that player gains 2 life for each creature they control.

Ajani Goldmane

+1: You gain 2 life.
−1: Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.
−6: Create a white Avatar creature token. It has "This creature's power and toughness are each equal to your life total."