Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Lay Down Arms

Exile target creature with mana value less than or equal to the number of Plains you control. Its controller gains 3 life.

Eidolon of Rhetoric

Each player can't cast more than one spell each turn.

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.

Deep Gnome Terramancer

Flash
Mold Earth — Whenever one or more lands enter under an opponent's control without being played, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle. Do this only once each turn.

Enlightened Tutor

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

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard Eiganjo, Seat of the Empire: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Flickering Ward

Enchant creature
As Flickering Ward enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Flickering Ward.
{W}: Return Flickering Ward to its owner's hand.

Mesa Enchantress

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

Benevolent Blessing

Flash
Enchant creature
As Benevolent Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Auras and Equipment you control that are already attached to it.

Rogue's Passage

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

Jeweled Lotus

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

Rebuff the Wicked

Counter target spell that targets a permanent you control.

Drannith Magistrate

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

Swift Reconfiguration

Flash
Enchant creature or Vehicle
Enchanted permanent is a Vehicle artifact with crew 5 and it loses all other card types. (It's not a creature unless it's crewed.)

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Snow-Covered Plains

Mask of Law and Grace

Enchant creature
Enchanted creature has protection from black and from red.

Chains of Custody

Enchant creature you control
When Chains of Custody enters, exile target nonland permanent an opponent controls until Chains of Custody leaves the battlefield.
Enchanted creature has ward {2}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Generous Gift

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

Timely Ward

You may cast Timely Ward as though it had flash if it targets a commander.
Enchant creature
Enchanted creature has indestructible.

Rashel, Fist of Torm

Double strike
Auras you control have exalted. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Moon-Blessed Cleric

Divine Intervention — When Moon-Blessed Cleric enters, you may search your library for an enchantment card, reveal it, then shuffle and put that card on top.

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.")

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, Emperor's Voice, then shuffle.

Ossification

Enchant basic land you control
When Ossification enters, exile target creature or planeswalker an opponent controls until Ossification leaves the battlefield.

Sigarda's Aid

You may cast Aura and Equipment spells as though they had flash.
Whenever an Equipment you control enters, you may attach it to target creature you control.

Unquestioned Authority

Enchant creature
When Unquestioned Authority enters, draw a card.
Enchanted creature has protection from creatures.

Flagstones of Trokair

{T}: Add {W}.
When Flagstones of Trokair is put into a graveyard from the battlefield, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Serra's Sanctum

{T}: Add {W} for each enchantment you control.

Battle Mastery

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

Kor Spiritdancer

Kor Spiritdancer gets +2/+2 for each Aura attached to it.
Whenever you cast an Aura spell, you may draw a card.

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.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Arcane Signet

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

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.

Felidar Umbra

Enchant creature
Enchanted creature has lifelink.
{1}{W}: Attach Felidar Umbra to target creature you control.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Sentinel's Eyes

Enchant creature
Enchanted creature gets +1/+1 and has vigilance.
Escape—{W}, Exile two other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Alseid of Life's Bounty

Lifelink
{1}, Sacrifice Alseid of Life's Bounty: Target creature or enchantment you control gains protection from the color of your choice until end of turn.

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.

Vanquish the Horde

This spell costs {1} less to cast for each creature on the battlefield.
Destroy all creatures.

Pariah

Enchant creature
All damage that would be dealt to you is dealt to enchanted creature instead.

Shielded by Faith

Enchant creature
Enchanted creature has indestructible.
Whenever a creature enters, you may attach Shielded by Faith to that creature.

Grand Abolisher

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

Ethereal Armor

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

Gryff's Boon

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

Sage's Reverie

Enchant creature
When Sage's Reverie enters, draw a card for each Aura you control that's attached to a creature.
Enchanted creature gets +1/+1 for each Aura you control that's attached to a creature.

Replenish

Return all enchantment cards from your graveyard to the battlefield. (Auras with nothing to enchant remain in your graveyard.)

Lotus Petal

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

Winds of Rath

Destroy all creatures that aren't enchanted. They can't be regenerated.

Heliod's Pilgrim

When Heliod's Pilgrim enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Archon of Emeria

Flying
Each player can't cast more than one spell each turn.
Nonbasic lands your opponents control enter tapped.

Rune of Sustenance

Enchant permanent
When Rune of Sustenance enters, draw a card.
As long as enchanted permanent is a creature, it has lifelink.
As long as enchanted permanent is an Equipment, it has "Equipped creature has lifelink."

Karametra's Blessing

Target creature gets +2/+2 until end of turn. If it's an enchanted creature or enchantment creature, it also gains 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.)

Daybreak Coronet

Enchant creature with another Aura attached to it
Enchanted creature gets +3/+3 and has first strike, vigilance, and lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)

Helm of the Gods

Equipped creature gets +1/+1 for each enchantment you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Hushbringer

Flying, lifelink
Creatures entering or dying don't cause abilities to trigger.

Cho-Manno's Blessing

Flash
Enchant creature
As Cho-Manno's Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Cho-Manno's Blessing.

Plains

Shield of Duty and Reason

Enchant creature
Enchanted creature has protection from green and from blue.

Triclopean Sight

Flash
Enchant creature
When Triclopean Sight enters, untap enchanted creature.
Enchanted creature gets +1/+1 and has vigilance.

Spirit Link

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Whenever enchanted creature deals damage, you gain that much life.

Sram, Senior Edificer

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Thran Power Suit

Equipped creature gets +1/+1 for each Aura and Equipment attached to it and has ward {2}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

All That Glitters

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

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.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Fateful Absence

Destroy target creature or planeswalker. Its controller investigates. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Spirit Mantle

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

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.

Transcendent Envoy

Flying
Aura spells you cast cost {1} less to cast.

Sol Ring

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Aven Mindcensor

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

Light of Promise

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

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}.