Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Mild-Mannered Librarian

{3}{G}: This creature becomes a Werewolf. Put two +1/+1 counters on it and you draw a card. Activate only once.

Lifecrafter's Bestiary

At the beginning of your upkeep, scry 1.
Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

Full Moon's Rise

Werewolf creatures you control get +1/+0 and have trample.
Sacrifice this enchantment: Regenerate all Werewolf creatures you control.

Storm-Charged Slasher

At the beginning of combat on your turn, target creature you control gets +2/+0 and gains trample and haste until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Reckless Stormseeker

At the beginning of combat on your turn, target creature you control gets +1/+0 and gains haste until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Reckless Stormseeker // Storm-Charged Slasher

Kessig Wolf Run

{T}: Add {C}.
{X}{R}{G}, {T}: Target creature gets +X/+0 and gains trample until end of turn.

Fangblade Eviscerator

{1}{R}: This creature gets +1/+0 and gains first strike until end of turn.
{4}{R}: Creatures you control get +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Fangblade Brigand

{1}{R}: This creature gets +1/+0 and gains first strike until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Fangblade Brigand // Fangblade Eviscerator

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard this card: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Hollowhenge Overlord

Flash
At the beginning of your upkeep, for each creature you control that's a Wolf or a Werewolf, create a 2/2 green Wolf creature token.

Hollowhenge Huntmaster

Hexproof
Other permanents you control have hexproof.
At the beginning of combat on your turn, put two +1/+1 counters on each creature you control.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Avabruck Caretaker

Hexproof
At the beginning of combat on your turn, put two +1/+1 counters on another target creature you control.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Avabruck Caretaker // Hollowhenge Huntmaster

Howlpack Resurgence

Flash
Each creature you control that's a Wolf or a Werewolf gets +1/+1 and has trample.

Nightpack Ambusher

Flash
Other Wolves and Werewolves you control get +1/+1.
At the beginning of your end step, if you didn't cast a spell this turn, create a 2/2 green Wolf creature token.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Ravager of the Fells

Trample
Whenever this creature transforms into Ravager of the Fells, it deals 2 damage to target opponent or planeswalker and 2 damage to up to one target creature that player or that planeswalker's controller controls.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Huntmaster of the Fells

Whenever this creature enters or transforms into Huntmaster of the Fells, create a 2/2 green Wolf creature token and you gain 2 life.
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Huntmaster of the Fells // Ravager of the Fells

Ranger Class

(Gain the next level as a sorcery to add its ability.)
When this Class enters, create a 2/2 green Wolf creature token.
{1}{G}: Level 2
Whenever you attack, put a +1/+1 counter on target attacking creature.
{3}{G}: Level 3
You may look at the top card of your library any time.
You may cast creature spells from the top of your library.

Tovolar's Packleader

Whenever this creature enters or attacks, create two 2/2 green Wolf creature tokens.
{2}{G}{G}: Another target Wolf or Werewolf you control fights target creature you don't control.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Tovolar's Huntmaster

When this creature enters, create two 2/2 green Wolf creature tokens.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Tovolar's Huntmaster // Tovolar's Packleader

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Terror of Kruin Pass

Double strike
Werewolves you control have menace. (A creature with menace can't be blocked except by two or more creatures.)
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Kruin Outlaw

First strike
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Kruin Outlaw // Terror of Kruin Pass

Nature's Claim

Destroy target artifact or enchantment. Its controller gains 4 life.

Dire-Strain Rampage

Destroy target artifact, enchantment, or land. If a land was destroyed this way, its controller may search their library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. Otherwise, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Flashback {3}{R}{G}

Arcane Signet

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

Village Reavers

Wolves and Werewolves you control have haste.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Village Watch

Haste
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Village Watch // Village Reavers

Lord of the Ulvenwald

Other Wolves and Werewolves you control get +1/+1.
Whenever this creature attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Kessig Naturalist

Whenever this creature attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Kessig Naturalist // Lord of the Ulvenwald

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

Immerwolf

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Each other creature you control that's a Wolf or a Werewolf gets +1/+1.
Non-Human Werewolves you control can't transform.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cultivate

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Sword of Body and Mind

Equipped creature gets +2/+2 and has protection from green and from blue.
Whenever equipped creature deals combat damage to a player, you create a 2/2 green Wolf creature token and that player mills ten cards.
Equip {2}

Krallenhorde Howler

Creature spells you cast cost {1} less to cast.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Duskwatch Recruiter

{2}{G}: Look at the top three cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Duskwatch Recruiter // Krallenhorde Howler

Untamed Pup

Trample
Other Wolves and Werewolves you control have trample.
{3}{G}: Put a +1/+1 counter on target creature.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Hound Tamer

Trample
{3}{G}: Put a +1/+1 counter on target creature.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Hound Tamer // Untamed Pup

Arlinn, the Moon's Fury

Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)
+2: Add {R}{G}.
0: Until end of turn, Arlinn becomes a 5/5 Werewolf creature with trample, indestructible, and haste.

Arlinn, the Pack's Hope

Daybound (If a player casts no spells during their own turn, it becomes night next turn.)
+1: Until your next turn, you may cast creature spells as though they had flash, and each creature you control enters with an additional +1/+1 counter on it.
−3: Create two 2/2 green Wolf creature tokens.

Arlinn, the Pack's Hope // Arlinn, the Moon's Fury

Moonmist

Transform all Humans. Prevent all combat damage that would be dealt this turn by creatures other than Werewolves and Wolves. (Only double-faced cards can be transformed.)

Zoological Study

Mill five cards, then return a creature card milled this way to your hand. (Then exile this card. You may cast the artifact later from exile.)

Monster Manual

{1}{G}, {T}: You may put a creature card from your hand onto the battlefield.

Monster Manual // Zoological Study

Howlpack Alpha

Each other creature you control that's a Werewolf or a Wolf gets +1/+1.
At the beginning of your end step, create a 2/2 green Wolf creature token.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Mayor of Avabruck

Other Human creatures you control get +1/+1.
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Mayor of Avabruck // Howlpack Alpha

Tovolar's Magehunter

Whenever an opponent casts a spell, this creature deals 2 damage to that player.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Mondronen Shaman

At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Mondronen Shaman // Tovolar's Magehunter

Arlinn, Embraced by the Moon

+1: Creatures you control get +1/+1 and gain trample until end of turn.
−1: Arlinn deals 3 damage to any target. Transform Arlinn.
−6: You get an emblem with "Creatures you control have haste and '{T}: This creature deals damage equal to its power to any target.'"

Arlinn Kord

+1: Until end of turn, up to one target creature gets +2/+2 and gains vigilance and haste.
0: Create a 2/2 green Wolf creature token. Transform Arlinn Kord.

Arlinn Kord // Arlinn, Embraced by the Moon

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Wolf Strike

Target creature you control gets +2/+0 until end of turn if it's night. Then it deals damage equal to its power to target creature you don't control.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Forest

Howlpack Avenger

Whenever a permanent you control is dealt damage, this creature deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Ill-Tempered Loner

Whenever this creature is dealt damage, it deals that much damage to any target.
{1}{R}: This creature gets +2/+0 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Ill-Tempered Loner // Howlpack Avenger

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Command Tower

Sol Ring

Werewolf Pack Leader

Pack tactics — Whenever this creature attacks, if you attacked with creatures with total power 6 or greater this combat, draw a card.
{3}{G}: Until end of turn, this creature has base power and toughness 5/3, gains trample, and isn't a Human.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Sword of Hearth and Home

Equipped creature gets +2/+2 and has protection from green and from white.
Whenever equipped creature deals combat damage to a player, exile up to one target creature you own, then search your library for a basic land card. Put both cards onto the battlefield under your control, then shuffle.
Equip {2}

Master of the Wild Hunt

At the beginning of your upkeep, create a 2/2 green Wolf creature token.
{T}: Tap all untapped Wolf creatures you control. Each Wolf tapped this way deals damage equal to its power to target creature. That creature deals damage equal to its power divided as its controller chooses among any number of those Wolves.

Wildsong Howler

Whenever this creature enters or transforms into Wildsong Howler, look at the top six cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Howlpack Piper

This spell can't be countered.
{1}{G}, {T}: You may put a creature card from your hand onto the battlefield. If it's a Wolf or Werewolf, untap this creature. Activate only as a sorcery.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Howlpack Piper // Wildsong Howler

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Vildin-Pack Alpha

Whenever a Werewolf you control enters, you may transform it.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Geier Reach Bandit

Haste
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Geier Reach Bandit // Vildin-Pack Alpha

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Bow of Nylea

Attacking creatures you control have deathtouch.
{1}{G}, {T}: Choose one —
• Put a +1/+1 counter on target creature.
• Bow of Nylea deals 2 damage to target creature with flying.
• You gain 3 life.
• Put up to four target cards from your graveyard on the bottom of your library in any order.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Neyith of the Dire Hunt

Whenever one or more creatures you control fight or become blocked, draw a card.
At the beginning of combat on your turn, you may pay {2}{R/G}. If you do, double target creature's power until end of turn. That creature must be blocked this combat if able. ({R/G} can be paid with either {R} or {G}.)

The Celestus

If it's neither day nor night, it becomes day as The Celestus enters.
{T}: Add one mana of any color.
{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.
Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.

Tovolar, the Midnight Scourge

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
{X}{R}{G}: Target Wolf or Werewolf you control gets +X/+0 and gains trample until end of turn.
Nightbound

Tovolar, Dire Overlord

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
At the beginning of your upkeep, if you control three or more Wolves and/or Werewolves, it becomes night. Then transform any number of Human Werewolves you control.
Daybound

Tovolar, Dire Overlord // Tovolar, the Midnight Scourge

Wing Shredder

Reach
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Bird Admirer

Reach
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Bird Admirer // Wing Shredder

Frenzied Trapbreaker

{1}, Sacrifice this creature: Destroy target artifact or enchantment.
Whenever this creature attacks, destroy target artifact or enchantment defending player controls.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Outland Liberator

{1}, Sacrifice this creature: Destroy target artifact or enchantment.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Outland Liberator // Frenzied Trapbreaker

Moonscarred Werewolf

Vigilance
{T}: Add {G}{G}.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform this creature.

Scorned Villager

{T}: Add {G}.
At the beginning of each upkeep, if no spells were cast last turn, transform this creature.

Scorned Villager // Moonscarred Werewolf

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Hunter's Insight

Choose target creature you control. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.