Mystic Crusader

Protection from black and from red
Threshold — As long as seven or more cards are in your graveyard, Mystic Crusader gets +1/+1 and has flying.

Mystic Penitent

Vigilance
Threshold — As long as seven or more cards are in your graveyard, Mystic Penitent gets +1/+1 and has flying.

Resilient Wanderer

First strike
Discard a card: Resilient Wanderer gains protection from the color of your choice until end of turn.

Shadow Rift

Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)
Draw a card.

Late to Dinner

Return target creature card from your graveyard to the battlefield. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Mystic Visionary

Threshold — Mystic Visionary has flying as long as seven or more cards are in your graveyard.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Consider

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

Snow-Covered Island

Stonehorn Dignitary

When Stonehorn Dignitary enters, target opponent skips their next combat phase.

Mystic Zealot

Threshold — As long as seven or more cards are in your graveyard, Mystic Zealot gets +1/+1 and has flying.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Citadel Gate

Citadel Gate enters tapped.
As Citadel Gate enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Tireless Tribe

Discard a card: Tireless Tribe gets +0/+4 until end of turn.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Snow-Covered Plains

Valor

First strike
As long as Valor is in your graveyard and you control a Plains, creatures you control have first strike.

Inside Out

Switch target creature's power and toughness until end of turn.
Draw a card.

Prismatic Strands

Prevent all damage that sources of the color of your choice would deal this turn.
Flashback—Tap an untapped white creature you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Standard Bearer

While an opponent is choosing targets as part of casting a spell they control or activating an ability they control, that player must choose at least one Flagbearer on the battlefield if able.

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)