Livaan, Cultist of Tiamat

Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value.
Choose a Background (You can have a Background as a second commander.)

Firebrand Archer

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Dreadhorde Arcanist

Trample
Whenever this creature attacks, you may cast target instant or sorcery card with mana value less than or equal to this creature's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Nature's Will

Whenever one or more creatures you control deal combat damage to a player, tap all lands that player controls and untap all lands you control.

The Howling Abomination

Haste
The Howling Abomination has trample as long as you've cast three or more spells this turn.
Whenever The Howling Abomination becomes the target of a spell, it gets +2/+2 until end of turn and deals 2 damage to each opponent.

Keen Sense

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

Forest

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Blossoming Defense

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Glaring Spotlight

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
{3}, Sacrifice this artifact: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Tamiyo's Safekeeping

Target permanent you control gains hexproof and indestructible until end of turn. You gain 2 life. (A permanent with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Talisman of Impulse

{T}: Add {C}.
{T}: Add {R} or {G}. This artifact deals 1 damage to you.

Psychotic Fury

Target multicolored creature gains double strike until end of turn.
Draw a card.

Sol Ring

Barroom Brawl

Target creature you control fights target creature the opponent to your left controls. Then that player may copy this spell and may choose new targets for the copy.

Wooded Ridgeline

({T}: Add {R} or {G}.)
This land enters tapped.

Poison the Blade

Target creature gains deathtouch until end of turn.
Draw a card.

Arachnoid Adaptation

Target creature gets +2/+2 and gains reach until end of turn. Untap it.

Storm the Seedcore

Distribute four +1/+1 counters among up to four target creatures you control. Creatures you control gain vigilance and trample until end of turn.

Fists of Flame

Draw a card. Until end of turn, target creature gains trample and gets +1/+0 for each card you've drawn this turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

Cosmic Hunger

Target creature you control deals damage equal to its power to another target creature, planeswalker, or battle.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Mountain

Blazing Crescendo

Target creature gets +3/+1 until end of turn.
Exile the top card of your library. Until the end of your next turn, you may play that card.

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (A creature with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Umezawa's Jitte

Whenever equipped creature deals combat damage, put two charge counters on Umezawa's Jitte.
Remove a charge counter from Umezawa's Jitte: Choose one —
• Equipped creature gets +2/+2 until end of turn.
• Target creature gets -1/-1 until end of turn.
• You gain 2 life.
Equip {2}

Twinferno

Choose one —
• When you cast your next instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
• Target creature you control gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Ancestral Anger

Target creature gains trample and gets +X/+0 until end of turn, where X is 1 plus the number of cards named Ancestral Anger in your graveyard.
Draw a card.

Runechanter's Pike

Equipped creature has first strike and gets +X/+0, where X is the number of instant and sorcery cards in your graveyard.
Equip {2}

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, this creature deals 1 damage to each opponent.

Alpha Authority

Enchant creature
Enchanted creature has hexproof and can't be blocked by more than one creature.

Wrenn's Resolve

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Timeless Witness

When this creature enters, return target card from your graveyard to your hand.
Eternalize {5}{G}{G} ({5}{G}{G}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Human Shaman with no mana cost. Eternalize only as a sorcery.)

Evolving Wilds

Command Tower

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

Arcane Signet

Free from Flesh

Target creature gets +2/+2 until end of turn. Put two oil counters on it.

Fellwar Stone

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

Season of Growth

Whenever a creature you control enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Whenever you cast a spell that targets a creature you control, draw a card.

Embiggen

Until end of turn, target non-Brushwagg creature gets +1/+1 for each supertype, card type, and subtype it has.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Snakeskin Veil

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Bite Down

Target creature you control deals damage equal to its power to target creature or planeswalker you don't control.

Questing Beast

Vigilance, deathtouch, haste
Questing Beast can't be blocked by creatures with power 2 or less.
Combat damage that would be dealt by creatures you control can't be prevented.
Whenever Questing Beast deals combat damage to an opponent, it deals that much damage to target planeswalker that player controls.

Blisterspit Gremlin

{1}, {T}: This creature deals 1 damage to each opponent.
Whenever you cast a noncreature spell, untap this creature.

Cultivate

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.

Fertilid's Favor

Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles. Put two +1/+1 counters on up to one target artifact or creature.

Castle Embereth

This land enters tapped unless you control a Mountain.
{T}: Add {R}.
{1}{R}{R}, {T}: Creatures you control get +1/+0 until end of turn.

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice this land: Put an indestructible counter on target God.

Ruthless Predation

Target creature you control gets +1/+2 until end of turn. It fights target creature you don't control. (Each deals damage equal to its power to the other.)

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Ranger's Guile

Target creature you control gets +1/+1 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Nature's Lore

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

Headlong Rush

Attacking creatures gain first strike until end of turn.

Tandem Takedown

Up to two target creatures you control each get +1/+0 until end of turn. They each deal damage equal to their power to another target creature, planeswalker, or battle.

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.

Looming Spires

Looming Spires enters tapped.
When Looming Spires enters, target creature gets +1/+1 and gains first strike until end of turn.
{T}: Add {R}.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Gruul Signet

Akki Battle Squad

Whenever one or more modified creatures you control attack, untap all modified creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn. (Equipment, Auras you control, and counters are modifications.)

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Charge Through

Target creature gains trample until end of turn.
Draw a card.

Gaea's Gift

Put a +1/+1 counter on target creature you control. It gains reach, trample, hexproof, and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Infectious Bite

Target creature you control deals damage equal to its power to target creature you don't control. Each opponent gets a poison counter.

Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Electrostatic Infantry

Trample
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on this creature.

Cinder Glade

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

Gruul Charm

Choose one —
• Creatures without flying can't block this turn.
• Gain control of all permanents you own.
• Gruul Charm deals 3 damage to each creature with flying.

Massive Might

Target creature gets +2/+2 and gains trample until end of turn.

Game Trail

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

Captain Ripley Vance

Whenever you cast your third spell each turn, put a +1/+1 counter on Captain Ripley Vance, then it deals damage equal to its power to any target.

Copperline Gorge

This land enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {G}.