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.)

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Selesnya Sanctuary

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{W}.

Fortified Village

As this land enters, you may reveal a Forest or Plains card from your hand. If you don't, this land enters tapped.
{T}: Add {G} or {W}.

Wildsear, Scouring Maw

Trample
Enchantment spells you cast from your hand have cascade. (Whenever you cast an enchantment spell from your hand, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Jukai Naturalist

Lifelink
Enchantment spells you cast cost {1} less to cast.

Feather of Flight

Flash
Enchant creature
When this Aura enters, draw a card.
Enchanted creature gets +1/+0 and has flying.

Forest

Warbriar Blessing

Enchant creature you control
When this Aura enters, enchanted creature fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)
Enchanted creature gets +0/+2.

Battle Mastery

Enchant creature
Enchanted creature has double strike. (It deals both first-strike and regular combat damage.)

Indestructibility

Enchant permanent
Enchanted permanent has indestructible. (Effects that say "destroy" don't destroy that permanent. A creature with indestructible can't be destroyed by damage.)

Gylwain, Casting Director

Whenever Gylwain or another nontoken creature you control enters, choose one —
• Create a Royal Role token attached to that creature.
• Create a Sorcerer Role token attached to that creature.
• Create a Monster Role token attached to that creature.

Atraxa's Fall

Destroy target artifact, battle, enchantment, or creature with flying.

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Setessan Champion

Constellation — Whenever an enchantment you control enters, put a +1/+1 counter on this creature and draw a card.

Sram, Senior Edificer

Whenever you cast an Aura, Equipment, or Vehicle spell, draw a card.

Verduran Enchantress

Whenever you cast an enchantment spell, you may draw a card.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Umbra Mystic

Auras attached to permanents you control have umbra armor. (If an enchanted permanent you control would be destroyed, instead remove all damage from it and destroy an Aura attached to it.)

Unbridled Growth

Enchant land
Enchanted land has "{T}: Add one mana of any color."
Sacrifice this Aura: Draw a card.

Eidolon of Blossoms

Constellation — Whenever this creature or another enchantment you control enters, draw a card.

Mirari's Wake

Creatures you control get +1/+1.
Whenever you tap a land for mana, add one mana of any type that land produced.

Sungrass Prairie

Enchantress's Presence

Whenever you cast an enchantment spell, draw a card.

Racecourse Fury

Enchant land
Enchanted land has "{T}: Target creature gains haste until end of turn."

Keen Sense

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Golden-Tail Trainer

Aura and Equipment spells you cast cost {X} less to cast, where X is this creature's power.
Whenever this creature attacks, other modified creatures you control get +X/+X until end of turn, where X is this creature's power. (Equipment, Auras you control, and counters are modifications.)

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Ondu Spiritdancer

Whenever an enchantment you control enters, you may create a token that's a copy of it. Do this only once each turn.

Return to Nature

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

Preston Garvey, Minuteman

At the beginning of combat on your turn, create a green Aura enchantment token named Settlement attached to up to one target land you control. It has enchant land and "Enchanted land has '{T}: Add one mana of any color.'"
Whenever Preston Garvey attacks, untap each enchanted permanent you control.

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Satyr Enchanter

Gryff's Boon

Enchant creature
Enchanted creature gets +1/+0 and has flying.
{3}{W}: Return this card from your graveyard to the battlefield attached to target creature. Activate only as a sorcery.

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.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.

Mesa Enchantress

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Mazzy, Truesword Paladin

Whenever an enchanted creature attacks one of your opponents, it gets +2/+0 and gains trample until end of turn.
Whenever an Aura you control is put into your graveyard from the battlefield, exile it. Until the end of your next turn, you may cast that card.

Shield of the Oversoul

Enchant creature
As long as enchanted creature is green, it gets +1/+1 and has indestructible. (Damage and effects that say "destroy" don't destroy it. If its toughness is 0 or less, it still dies.)
As long as enchanted creature is white, it gets +1/+1 and has flying.

Reyav, Master Smith

Whenever a creature you control that's enchanted or equipped attacks, that creature gains double strike until end of turn.

Sol Ring

Chishiro, the Shattered Blade

Whenever an Aura or Equipment you control enters, create a 2/2 red Spirit creature token with menace.
At the beginning of your end step, put a +1/+1 counter on each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

Tanglespan Lookout

Whenever an Aura you control enters, draw a card.

Mountain

Hardened Escort

Whenever this creature attacks, another target creature you control gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Ellivere of the Wild Court

Whenever Ellivere enters or attacks, create a Virtuous Role token attached to another target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 for each enchantment you control.)
Whenever an enchanted creature you control deals combat damage to a player, draw a card.

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Sythis, Harvest's Hand

Whenever you cast an enchantment spell, you gain 1 life and draw a card.

Codsworth, Handy Helper

Commanders you control have ward {2}.
{T}: Add {W}{W}. Spend this mana only to cast Aura and/or Equipment spells.
{T}: Attach target Aura or Equipment you control to target creature you control. Activate only as a sorcery.

Composer of Spring

Constellation — Whenever an enchantment you control enters, you may put a land card from your hand onto the battlefield tapped. If you control six or more enchantments, instead you may put a creature or land card from your hand onto the battlefield tapped.

Sticky Fingers

Enchant creature
Enchanted creature has menace and "Whenever this creature deals combat damage to a player, create a Treasure token." (It can't be blocked except by two or more creatures. The token is an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
When enchanted creature dies, draw a card.

Mossfire Valley

Boon of the Spirit Realm

Constellation — Whenever this enchantment or another enchantment you control enters, put a blessing counter on this enchantment.
Creatures you control get +1/+1 for each blessing counter on this enchantment.

Jungle Shrine

This land enters tapped.
{T}: Add {R}, {G}, or {W}.

Abundant Growth

Enchant land
When this Aura enters, draw a card.
Enchanted land has "{T}: Add one mana of any color."

Light-Paws, Emperor's Voice

Whenever an Aura you control enters, if you cast it, you may search your library for an Aura card with mana value less than or equal to that Aura and with a different name than each Aura you control, put that card onto the battlefield attached to Light-Paws, then shuffle.

Llanowar Elves

Demonic Ruckus

Enchant creature
Enchanted creature gets +1/+1 and has menace and trample.
When this Aura is put into a graveyard from the battlefield, draw a card.
Plot {R} (You may pay {R} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Well Rested

Enchant creature
Enchanted creature has "Whenever this creature becomes untapped, put two +1/+1 counters on it, then you gain 2 life and draw a card. This ability triggers only once each turn."

Spirit Mantle

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

Idolized

Enchant creature
Enchanted creature has "Whenever this creature attacks alone, it gets +X/+X until end of turn, where X is the number of nonland permanents you control."

Plains

Starfield Mystic

Enchantment spells you cast cost {1} less to cast.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on this creature.

Herald of the Pantheon

Enchantment spells you cast cost {1} less to cast.
Whenever you cast an enchantment spell, you gain 1 life.

Bigger on the Inside

Enchant artifact or land
Enchanted permanent has "{T}: Target player adds two mana of any one color. The next spell they cast this turn has cascade." (When they cast their next spell, they exile cards from the top of their library until they exile a nonland card that costs less. They may cast it without paying its mana cost. They put the exiled cards on the bottom in a random order.)

Command Tower

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

Shardmage's Rescue

Flash
Enchant creature you control
As long as this Aura entered this turn, enchanted creature has hexproof.
Enchanted creature gets +1/+1.

Grim Reaper's Sprint

Morbid — This spell costs {3} less to cast if a creature died this turn.
Enchant creature
When this Aura enters, untap each creature you control. If it's your main phase, there is an additional combat phase after this phase.
Enchanted creature gets +2/+2 and has haste.

Sunbillow Verge

{T}: Add {W}.
{T}: Add {R}. Activate only if you control a Mountain or a Plains.

Sanctum Weaver

{T}: Add X mana of any one color, where X is the number of enchantments you control.

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Strong Back

Enchant creature
Equip abilities you activate that target enchanted creature cost {3} less to activate.
Aura spells you cast that target enchanted creature cost {3} less to cast.
Enchanted creature gets +2/+2 for each Aura and Equipment attached to it.

Rune of Might

Enchant permanent
When this Aura enters, draw a card.
As long as enchanted permanent is a creature, it gets +1/+1 and has trample.
As long as enchanted permanent is an Equipment, it has "Equipped creature gets +1/+1 and has trample."