Joust

Choose target creature you control and target creature you don't control. The creature you control gets +2/+1 until end of turn if it's a Knight. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Vantress Paladin

Flying
Adamant — If at least three blue mana was spent to cast this spell, Vantress Paladin enters with a +1/+1 counter on it.

Preening Champion

Flying
When Preening Champion enters, create a 1/1 blue and red Elemental creature token.

Radiant Flames

Converge — Radiant Flames deals X damage to each creature, where X is the number of colors of mana spent to cast this spell.

Mythos of Vadrok

Mythos of Vadrok deals 5 damage divided as you choose among any number of target creatures and/or planeswalkers. If {W}{U} was spent to cast this spell, until your next turn, those permanents can't attack or block and their activated abilities can't be activated.

Fireborn Knight

Double strike
{R/W}{R/W}{R/W}{R/W}: Fireborn Knight gets +1/+1 until end of turn.

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

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

Pacifism

Enchant creature
Enchanted creature can't attack or block.

Tori D'Avenant, Fury Rider

Vigilance, trample
Whenever Tori D'Avenant, Fury Rider attacks, all other attacking creatures you control get +1/+1 until end of turn. Other red attacking creatures you control gain trample until end of turn. Untap each other white attacking creature you control.

Weaselback Redcap

{1}{R}: Weaselback Redcap gets +2/+0 until end of turn.

Zhalfirin Lancer

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

Charmed Sleep

Enchant creature
When Charmed Sleep enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Lava Coil

Lava Coil deals 4 damage to target creature. If that creature would die this turn, exile it instead.

Island

Hieromancer's Cage

When Hieromancer's Cage enters, exile target nonland permanent an opponent controls until Hieromancer's Cage leaves the battlefield.

Mountain

Mesmerizing Dose

Enchant creature
When Mesmerizing Dose enters, tap enchanted creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Enchanted creature doesn't untap during its controller's untap step.

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

Burning-Yard Trainer

Trample, haste
When Burning-Yard Trainer enters, another target Knight you control gets +2/+2 and gains trample and haste until end of turn.

Wind-Scarred Crag

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {W}.

Venerable Knight

When Venerable Knight dies, put a +1/+1 counter on target Knight you control.

Garrison Griffin

Flying
Whenever Garrison Griffin attacks, target Knight you control gains flying until end of turn.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Inspiring Veteran

Slice and Dice

Slice and Dice deals 4 damage to each creature.
Cycling {2}{R} ({2}{R}, Discard this card: Draw a card.)
When you cycle Slice and Dice, you may have it deal 1 damage to each creature.

Citywide Bust

Destroy all creatures with toughness 4 or greater.

Rowan's Battleguard

First strike
As long as you control a Rowan planeswalker, Rowan's Battleguard gets +3/+0.

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.)

Rowan, Fearless Sparkmage

+1: Up to one target creature gets +3/+0 and gains first strike until end of turn.
−2: Rowan, Fearless Sparkmage deals 1 damage to each of up to two target creatures. Those creatures can't block this turn.
−9: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Bound in Gold

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

Fall from Favor

Enchant creature
When Fall from Favor enters, tap enchanted creature and you become the monarch.
Enchanted creature doesn't untap during its controller's untap step unless that player is the monarch.