Saiba Cryptomancer

Flash
Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Hexproof

Marshal of Zhalfir

Other Knights you control get +1/+1.
{W}{U}, {T}: Tap another target creature.

Zhalfirin Lancer

Whenever another Knight you control enters, Zhalfirin Lancer gets +1/+1 and gains vigilance until end of turn.

Halo-Charged Skaab

When Halo-Charged Skaab enters, each player mills two cards. Then you may put an instant, sorcery, or battle card from your graveyard on top of your library. (To mill two cards, a player puts the top two cards of their library into their graveyard.)

Order of the Alabaster Host

Whenever Order of the Alabaster Host becomes blocked by a creature, that creature gets -1/-1 until end of turn.

Order of the Mirror

{3}{W/P}: Transform Order of the Mirror. Activate only as a sorcery. ({W/P} can be paid with either {W} or 2 life.)

Order of the Mirror // Order of the Alabaster Host

Sigiled Sentinel

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Vigilance

Plains

Vertex Paladin

Flying
Vertex Paladin's power and toughness are each equal to the number of creatures you control.

Invasion of Xerex

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Xerex enters, return up to one target creature to its owner's hand.

Invasion of Xerex // Vertex Paladin

Tidal Terror

Whenever Tidal Terror attacks, you may tap two other untapped creatures you control. If you do, Tidal Terror can't be blocked this turn.
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Negate

Realmbreaker's Grasp

Enchant artifact or creature
Enchanted permanent can't attack or block, and its activated abilities can't be activated unless they're mana abilities.

Assimilate Essence

Counter target creature or battle spell unless its controller pays {4}. If they do, you incubate 2. (Create an Incubator token with two +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)

Bola Slinger

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Whenever this creature attacks, tap target artifact or creature an opponent controls.

Temporal Cleansing

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
The owner of target nonland permanent puts it into their library second from the top or on the bottom.

Cut Short

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy target planeswalker that was activated this turn or tapped creature.

Knight of the New Coalition

Vigilance
When Knight of the New Coalition enters, create a 2/2 white and blue Knight creature token with vigilance.

Island

Swordsworn Cavalier

Swordsworn Cavalier has first strike as long as another Knight entered the battlefield under your control this turn.

Protocol Knight

When Protocol Knight enters, tap target creature an opponent controls. Put a stun counter on that creature if you control another Knight. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Artistic Refusal

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Choose one or both —
• Counter target spell.
• Draw two cards, then discard a card.