Thunderhead Squadron

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.)
Flying

Valorous Steed

Vigilance (Attacking doesn't cause this creature to tap.)
When Valorous Steed enters, create a 2/2 white Knight creature token with vigilance.

War Falcon

Flying
War Falcon can't attack unless you control a Knight or a Soldier.

Knight of the Mists

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
When Knight of the Mists enters, you may pay {U}. If you don't, destroy target Knight and it can't be regenerated.

Marshal of Zhalfir

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

Pterodon Knight

Pterodon Knight has flying as long as you control a Dinosaur.

Capashen Knight

First strike (This creature deals combat damage before creatures without first strike.)
{1}{W}: Capashen Knight gets +1/+0 until end of turn.

Knight of Sorrows

Knight of Sorrows can block an additional creature each combat.
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Swordsworn Cavalier

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

Rider in Need

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the creature later from exile.)

Lonesome Unicorn

Lonesome Unicorn // Rider in Need

Knight of Valor

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
{1}{W}: Each creature without flanking blocking Knight of Valor gets -1/-1 until end of turn. Activate only once each turn.

Garrison Griffin

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

Knights of Dol Amroth

Whenever you draw your second card each turn, put a +1/+1 counter on Knights of Dol Amroth.

Attended Knight

First strike
When Attended Knight enters, create a 1/1 white Soldier creature token.

Sacred Knight

Sacred Knight can't be blocked by black and/or red creatures.

Kor Line-Slinger

{T}: Tap target creature with power 3 or less.

Shining Armor

Flash
When Shining Armor enters, attach it to target Knight you control.
Equipped creature gets +0/+2 and has vigilance.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Opal Champion

When an opponent casts a creature spell, if Opal Champion is an enchantment, Opal Champion becomes a 3/3 Knight creature with first strike.

Springjack Knight

Whenever Springjack Knight attacks, clash with an opponent. If you win, target creature gains double strike until end of turn. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Littjara Kinseekers

Changeling (This card is every creature type.)
When Littjara Kinseekers enters, if you control three or more creatures that share a creature type, put a +1/+1 counter on Littjara Kinseekers, then scry 1.

Knight of Old Benalia

Suspend 5—{W} (Rather than cast this card from your hand, you may pay {W} and exile it with five time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
When Knight of Old Benalia enters, other creatures you control get +1/+1 until end of turn.

Knighted Myr

{2}{W}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Knighted Myr, it gains double strike until end of turn.

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.

Recruitment Drive

Roll a d20.
1—9 | Create two 1/1 white Soldier creature tokens.
10—19 | Create two 2/2 white Knight creature tokens.
20 | Create three 2/2 white Knight creature tokens.

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.)

Femeref Knight

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
{W}: Femeref Knight gains vigilance until end of turn.

Armory of Iroas

Whenever equipped creature attacks, put a +1/+1 counter on it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Azorius Knight-Arbiter

Vigilance
Azorius Knight-Arbiter can't be blocked.

Call the Cavalry

Create two 2/2 white Knight creature tokens with vigilance.

Gallant Cavalry

Vigilance (Attacking doesn't cause this creature to tap.)
When Gallant Cavalry enters, create a 2/2 white Knight creature token with vigilance.

Enchant creature
Enchanted creature gets +2/+2, has first strike, and is a Knight in addition to its other types. (It deals combat damage before creatures without first strike.)

Knight Watch

Zhalfirin Knight

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
{W}{W}: Zhalfirin Knight gains first strike until end of turn.

Knightly Valor

Enchant creature
When Knightly Valor enters, create a 2/2 white Knight creature token with vigilance. (Attacking doesn't cause it to tap.)
Enchanted creature gets +2/+2 and has vigilance.

Errand of Duty

Create a 1/1 white Knight creature token with banding. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Hopeful Vigil

When Hopeful Vigil enters, create a 2/2 white Knight creature token with vigilance.
When Hopeful Vigil is put into a graveyard from the battlefield, scry 2.
{2}{W}: Sacrifice Hopeful Vigil.

Preening Champion

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

Lyev Skyknight

Flying
When Lyev Skyknight enters, detain target nonland permanent an opponent controls. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sunspire Gatekeepers

When Sunspire Gatekeepers enters, if you control two or more Gates, create a 2/2 white Knight creature token with vigilance.