Sigiled Sentinel

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

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

Belenon War Anthem

Invasion of Belenon

(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 Belenon enters the battlefield, create a 2/2 white and blue Knight creature token with vigilance.

Invasion of Belenon // Belenon War Anthem

Norn's Inquisitor

When Norn's Inquisitor enters the battlefield, 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.)
Whenever a permanent you control transforms into a Phyrexian, put a +1/+1 counter on it.

Plains

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Golden-Scale Aeronaut

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

Scrollshift

Exile up to one target artifact, creature, or enchantment you control, then return it to the battlefield under its owner's control.
Draw a card.

Protocol Knight

When Protocol Knight enters the battlefield, 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.)

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.

Seal from Existence

Ward {3} (Whenever this enchantment becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
When Seal from Existence enters the battlefield, exile target nonland permanent an opponent controls until Seal from Existence leaves the battlefield.

Raff, Weatherlight Stalwart

Whenever you cast an instant or sorcery spell, you may tap two untapped creatures you control. If you do, draw a card.
{3}{W}{W}: Creatures you control get +1/+1 and gain vigilance until end of turn.

Knight of the New Coalition

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

Swordsworn Cavalier

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

Chrome Host Seedshark

Flying
Whenever you cast a noncreature spell, incubate X, where X is that spell's mana value. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)

Angelic Intervention

Target creature or planeswalker you control gains protection from colorless or from the color of your choice until end of turn. If it's a creature, put a +1/+1 counter on it. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything with that quality.)

Island

Skyclave Invader

Flying
When this creature transforms into Skyclave Invader, look at the top card of your library. If it's a land card, you may put it onto the battlefield. If you don't put the card onto the battlefield, put it into your hand.

Skyclave Aerialist

Flying
{4}{G/P}: Transform Skyclave Aerialist. Activate only as a sorcery. ({G/P} can be paid with either {G} or 2 life.)