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.)

Cephalid Retainer

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

Puppeteer

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

Mystic Penitent

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

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.

Beloved Chaplain

Cephalid Scout

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

Island

Skycloud Egg

{2}, {T}, Sacrifice this artifact: Add {W}{U}. Draw a card.

Cephalid Broker

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

Abandoned Outpost

This land enters tapped.
{T}: Add {W}.
{T}, Sacrifice this land: Add one mana of any color.

Seafloor Debris

This land enters tapped.
{T}: Add {U}.
{T}, Sacrifice this land: 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.

Peek

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

Second Thoughts

Exile target attacking creature.
Draw a card.

Pilgrim of Justice

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

Cephalid Looter

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

Mystic Visionary

Threshold — This creature has flying as long as seven or more cards are in your graveyard.

Mystic Zealot

Threshold — As long as seven or more cards are in your graveyard, this creature 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.

Plains

Angelic Wall

Defender (This creature can't attack.)
Flying

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.

Blessed Orator

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.)

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.)

Mystic Crusader

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