Martyr's Cause

Sacrifice a creature: The next time a source of your choice would deal damage to any target this turn, prevent that damage.

Abdel Adrian, Gorion's Ward

When Abdel Adrian, Gorion's Ward enters, exile any number of other nonland permanents you control until Abdel Adrian leaves the battlefield. Create a 1/1 white Soldier creature token for each permanent exiled this way.
Choose a Background (You can have a Background as a second commander.)

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Cathar Commando

Flash (You may cast this spell any time you could cast an instant.)
{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Hope of Ghirapur

Flying
Sacrifice Hope of Ghirapur: Until your next turn, target player who was dealt combat damage by Hope of Ghirapur this turn can't cast noncreature spells.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Stonecoil Serpent

Reach, trample, protection from multicolored
Stonecoil Serpent enters with X +1/+1 counters on it.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Aviary Mechanic

When Aviary Mechanic enters, you may return another permanent you control to its owner's hand.

Recruiter of the Guard

When Recruiter of the Guard enters, you may search your library for a creature card with toughness 2 or less, reveal it, put it into your hand, then shuffle.

Drannith Magistrate

Your opponents can't cast spells from anywhere other than their hands.

Workshop Assistant

When Workshop Assistant dies, return another target artifact card from your graveyard to your hand.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Shield Sphere

Defender
Whenever Shield Sphere blocks, put a -0/-1 counter on it.

Lightning Greaves

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

Kami of False Hope

Sacrifice Kami of False Hope: Prevent all combat damage that would be dealt this turn.

Phyrexian Walker

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Ancient Den

Helm of Awakening

Aven Interrupter

Flash
Flying
When Aven Interrupter enters, exile target spell. It becomes plotted. (Its owner may cast it as a sorcery on a later turn without paying its mana cost.)
Spells your opponents cast from graveyards or from exile cost {2} more to cast.

Krark-Clan Ironworks

Filigree Familiar

When Filigree Familiar enters, you gain 2 life.
When Filigree Familiar dies, draw a card.

Shimmer Myr

Flash
You may cast artifact spells as though they had flash.

Mana Tithe

Counter target spell unless its controller pays {1}.

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Selfless Savior

Sacrifice Selfless Savior: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Liberator, Urza's Battlethopter

Flash
Flying
You may cast colorless spells and artifact spells as though they had flash.
Whenever you cast a spell, if the amount of mana spent to cast that spell is greater than Liberator, Urza's Battlethopter's power, put a +1/+1 counter on Liberator.

Citywide Bust

Destroy all creatures with toughness 4 or greater.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Mishra's Workshop

{T}: Add {C}{C}{C}. Spend this mana only to cast artifact spells.

Delney, Streetwise Lookout

Creatures you control with power 2 or less can't be blocked by creatures with power 3 or greater.
If an ability of a creature you control with power 2 or less triggers, that ability triggers an additional time.

Dauntless Dismantler

Artifacts your opponents control enter tapped.
{X}{X}{W}, Sacrifice Dauntless Dismantler: Destroy each artifact with mana value X.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Grinding Station

{T}, Sacrifice an artifact: Target player mills three cards.
Whenever an artifact enters, you may untap Grinding Station.

Trouble in Pairs

If an opponent would begin an extra turn, that player skips that turn instead.
Whenever an opponent attacks you with two or more creatures, draws their second card each turn, or casts their second spell each turn, you draw a card.

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

The Battle of Bywater

Destroy all creatures with power 3 or greater. Then create a Food token for each creature you control. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Ornithopter

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Arcane Signet

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

Boromir, Warden of the Tower

Vigilance
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.
Sacrifice Boromir, Warden of the Tower: Creatures you control gain indestructible until end of turn. The Ring tempts you.

Spirited Companion

When Spirited Companion enters, draw a card.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Cathodion

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.

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Soul Warden

Whenever another creature enters, you gain 1 life.

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Ashnod's Altar

Heliod, Sun-Crowned

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
Whenever you gain life, put a +1/+1 counter on target creature or enchantment you control.
{1}{W}: Another target creature gains lifelink until end of turn.

Salvager of Ruin

Sacrifice Salvager of Ruin: Choose target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand.

Loran of the Third Path

Vigilance
When Loran of the Third Path enters, destroy up to one target artifact or enchantment.
{T}: You and target opponent each draw a card.

Reprieve

Return target spell to its owner's hand.
Draw a card.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Circuit Mender

When Circuit Mender enters, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

Samwise the Stouthearted

Flash
When Samwise the Stouthearted enters, choose up to one target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand. Then the Ring tempts you.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Blasting Station

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Memnite

Sol Ring

Ranger-Captain of Eos

When Ranger-Captain of Eos enters, you may search your library for a creature card with mana value 1 or less, reveal it, put it into your hand, then shuffle.
Sacrifice Ranger-Captain of Eos: Your opponents can't cast noncreature spells this turn.

Silence

Your opponents can't cast spells this turn.

Teshar, Ancestor's Apostle

Flying
Whenever you cast a historic spell, return target creature card with mana value 3 or less from your graveyard to the battlefield. (Artifacts, legendaries, and Sagas are historic.)