Have

Azorius Knight-Arbiter

Vigilance
Azorius Knight-Arbiter can't be blocked.

Call the Cavalry

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

Knightly Valor

Enchant creature
When Knightly Valor enters the battlefield, 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.

Twinblade Paladin

Whenever you gain life, put a +1/+1 counter on Twinblade Paladin.
As long as you have 25 or more life, Twinblade Paladin has double strike. (It deals both first-strike and regular combat damage.)

Forebear's Blade

Equipped creature gets +3/+0 and has vigilance and trample.
Whenever equipped creature dies, attach Forebear's Blade to target creature you control.
Equip {3}

Knight of New Benalia

Josu Vess, Lich Knight

Kicker {5}{B} (You may pay an additional {5}{B} as you cast this spell.)
Menace
When Josu Vess, Lich Knight enters the battlefield, if it was kicked, create eight 2/2 black Zombie Knight creature tokens with menace.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters the battlefield, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Benalish Marshal

Knight of the Keep

Parhelion Patrol

Flying, vigilance
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Knights' Charge

Whenever a Knight you control attacks, each opponent loses 1 life and you gain 1 life.
{6}{W}{B}, Sacrifice Knights' Charge: Return all Knight creature cards from your graveyard to the battlefield.

Profane Insight

You draw a card and you lose 1 life. (Then exile this card. You may cast the creature later from exile.)

Foulmire Knight

Foulmire Knight // Profane Insight

Thistledown Liege

Flash
Other white creatures you control get +1/+1.
Other blue creatures you control get +1/+1.

Flight of Equenauts

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

Venerable Knight

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

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Breathless Knight

Flying, lifelink
Whenever Breathless Knight or another creature enters the battlefield under your control, if that creature entered from a graveyard or you cast it from a graveyard, put a +1/+1 counter on Breathless Knight.

Knight's Pledge

Enchant creature
Enchanted creature gets +2/+2.

Knight Exemplar

First strike (This creature deals combat damage before creatures without first strike.)
Other Knight creatures you control get +1/+1 and have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Knight of the Pilgrim's Road

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)

Sidar Jabari of Zhalfir

Eminence — Whenever you attack with one or more Knights, if Sidar Jabari of Zhalfir is in the command zone or on the battlefield, draw a card, then discard a card.
Flying, first strike
Whenever Sidar Jabari deals combat damage to a player, return target Knight creature card from your graveyard to the battlefield.

Resolute Rider

{W/B}{W/B}: Resolute Rider gains lifelink until end of turn.
{W/B}{W/B}{W/B}: Resolute Rider gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Gallant Cavalry

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

Aryel, Knight of Windgrace

Vigilance
{2}{W}, {T}: Create a 2/2 white Knight creature token with vigilance.
{B}, {T}, Tap X untapped Knights you control: Destroy target creature with power X or less.

Valiant Knight

Other Knights you control get +1/+1.
{3}{W}{W}: Knights you control gain double strike until end of turn.

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.)

Curry Favor

You gain X life and each opponent loses X life, where X is the number of Knights you control.

Smitten Swordmaster

Smitten Swordmaster // Curry Favor

Knight of Grace

First strike
Hexproof from black (This creature can't be the target of black spells or abilities your opponents control.)
Knight of Grace gets +1/+0 as long as any player controls a black permanent.

Danitha Capashen, Paragon

First strike, vigilance, lifelink
Aura and Equipment spells you cast cost {1} less to cast.

Markov Dreadknight

Flying
{2}{B}, Discard a card: Put two +1/+1 counters on Markov Dreadknight.

Mirran Crusader

Double strike, protection from black and from green

Ethersworn Adjudicator

Flying
{1}{W}{B}, {T}: Destroy target creature or enchantment.
{2}{U}: Untap Ethersworn Adjudicator.

Acclaimed Contender

When Acclaimed Contender enters the battlefield, if you control another Knight, look at the top five cards of your library. You may reveal a Knight, Aura, Equipment, or legendary artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Knight of Malice

First strike
Hexproof from white (This creature can't be the target of white spells or abilities your opponents control.)
Knight of Malice gets +1/+0 as long as any player controls a white permanent.

Getting

Tura Kennerüd, Skyknight

Flying
Whenever you cast an instant or sorcery spell, create a 1/1 white Soldier creature token.

Devoted Paladin

Beacon of Hope — When Devoted Paladin enters the battlefield, creatures you control get +1/+1 and gain vigilance until end of turn.

Coalition Skyknight

Flying
Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)