Spectral Procession

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

Getting

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.

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.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on Ajani's Pridemate.

Plains

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.

Martyr of Sands

{1}, Reveal X white cards from your hand, Sacrifice Martyr of Sands: You gain three times X life.

Soul Warden

Whenever another creature enters, you gain 1 life.

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.

Honor of the Pure

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.

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.

Gideon, Ally of Zendikar

+1: Until end of turn, Gideon, Ally of Zendikar becomes a 5/5 Human Soldier Ally creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
0: Create a 2/2 white Knight Ally creature token.
−4: You get an emblem with "Creatures you control get +1/+1."