Embolden

Prevent the next 4 damage that would be dealt this turn to any number of targets, divided as you choose.
Flashback {1}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Second Thoughts

Exile target attacking creature.
Draw a card.

Skycloud Egg

{2}, {T}, Sacrifice Skycloud Egg: Add {W}{U}. Draw a card.

Mystic Visionary

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

Seafloor Debris

Seafloor Debris enters tapped.
{T}: Add {U}.
{T}, Sacrifice Seafloor Debris: Add one mana of any color.

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Cephalid Scout

Flying
{2}{U}, Sacrifice a land: Draw a card.

Aven Windreader

Flying (This creature can't be blocked except by creatures with flying or reach.)
{1}{U}: Target player reveals the top card of their library.

Peek

Look at target player's hand.
Draw a card.

Mystic Penitent

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

Plains

Cephalid Looter

{T}: Target player draws a card, then discards a card.

Nomad Decoy

{W}, {T}: Tap target creature.
Threshold — {W}{W}, {T}: Tap two target creatures. Activate only if seven or more cards are in your graveyard.

Puppeteer

{U}, {T}: You may tap or untap target creature.

Think Tank

At the beginning of your upkeep, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Abandoned Outpost

Abandoned Outpost enters tapped.
{T}: Add {W}.
{T}, Sacrifice Abandoned Outpost: Add one mana of any color.

Island

Hallowed Healer

{T}: Prevent the next 2 damage that would be dealt to any target this turn.
Threshold — {T}: Prevent the next 4 damage that would be dealt to any target this turn. Activate only if seven or more cards are in your graveyard.

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Beloved Chaplain

Pilgrim of Justice

Protection from red
{W}, Sacrifice Pilgrim of Justice: The next time a red source of your choice would deal damage this turn, prevent that damage.

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.

Cephalid Broker

{T}: Target player draws two cards, then discards two cards.

Kirtar's Desire

Enchant creature
Enchanted creature can't attack.
Threshold — Enchanted creature can't block as long as seven or more cards are in your graveyard.

Angelic Wall

Defender (This creature can't attack.)
Flying

Cephalid Retainer

{U}{U}: Tap target creature without flying.

Blessed Orator

Mystic Zealot

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

Shelter

Target creature you control gains protection from the color of your choice until end of turn.
Draw a card.