March of Otherworldly Light

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Blight Pile

Defender
{2}{B}, {T}: Each opponent loses X life, where X is the number of creatures with defender you control.

Cut Down

Destroy target creature with total power and toughness 5 or less.

Shipwreck Marsh

Shipwreck Marsh enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Plains

Swamp

Stall for Time

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Tap up to two target creatures. If this spell was kicked, put a stun counter on each of those creatures. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Draw a card.

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Fading Hope

Return target creature to its owner's hand. If its mana value was 3 or less, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Shield-Wall Sentinel

Defender
When Shield-Wall Sentinel enters, you may search your library for a creature card with defender, reveal it, put it into your hand, then shuffle.

Wingmantle Chaplain

Defender
When Wingmantle Chaplain enters, create a 1/1 white Bird creature token with flying for each creature with defender you control.
Whenever another creature you control with defender enters, create a 1/1 white Bird creature token with flying.

Coral Colony

Defender
{1}{U}, {T}: Target player mills X cards, where X is the number of creatures you control with defender. (To mill a card, a player puts the top card of their library into their graveyard.)

Island

Shattered Sanctum

Shattered Sanctum enters tapped unless you control two or more other lands.
{T}: Add {W} or {B}.

Walking Bulwark

Defender
{2}: Until end of turn, target creature with defender gains haste, can attack as though it didn't have defender, and assigns combat damage equal to its toughness rather than its power. Activate only as a sorcery.

Deserted Beach

Deserted Beach enters tapped unless you control two or more other lands.
{T}: Add {W} or {U}.