Ajani's Welcome

Whenever a creature enters the battlefield under your control, you gain 1 life.

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."

Trostani, Selesnya's Voice

Whenever another creature enters the battlefield under your control, you gain life equal to that creature's toughness.
{1}{G}{W}, {T}: Populate. (Create a token that's a copy of a creature token you control.)

Ajani's Sunstriker

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Impassioned Orator

Whenever another creature enters the battlefield under your control, you gain 1 life.

Ajani, Mentor of Heroes

+1: Distribute three +1/+1 counters among one, two, or three target creatures you control.
+1: Look at the top four cards of your library. You may reveal an Aura, creature, or planeswalker card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
−8: You gain 100 life.

Ajani's Last Stand

Whenever a creature or planeswalker you control dies, you may sacrifice Ajani's Last Stand. If you do, create a 4/4 white Avatar creature token with flying.
When a spell or ability an opponent controls causes you to discard this card, if you control a Plains, create a 4/4 white Avatar creature token with flying.