Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Ghost Quarter

{T}: Add {C}.
{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Ranger of Eos

When Ranger of Eos enters, you may search your library for up to two creature cards with mana value 1 or less, reveal them, put them into your hand, then shuffle.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Elspeth, Knight-Errant

+1: Create a 1/1 white Soldier creature token.
+1: Target creature gets +3/+3 and gains flying until end of turn.
−8: You get an emblem with "Artifacts, creatures, enchantments, and lands you control have indestructible."

Squadron Hawk

Flying
When Squadron Hawk enters, you may search your library for up to three cards named Squadron Hawk, reveal them, put them into your hand, then shuffle.

Soul Warden

Whenever another creature enters, you gain 1 life.

Flagstones of Trokair

{T}: Add {W}.
When Flagstones of Trokair is put into a graveyard from the battlefield, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Wrath of God

Destroy all creatures. They can't be regenerated.

Honor of the Pure

Spectral Procession

Create three 1/1 white Spirit creature tokens with flying.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Plains

Auriok Champion

Protection from black and from red
Whenever another creature enters, you may gain 1 life.