maybe

Storm of Saruman

Ward {3}
Whenever you cast your second spell each turn, copy it, except the copy isn't legendary. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Have

Aetherflux Reservoir

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

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

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 token: Add one mana of any color.")

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Getting

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.

Archaeomancer's Map

When this artifact enters, search your library for up to two basic Plains cards, reveal them, put them into your hand, then shuffle.
Whenever a land an opponent controls enters, if that player controls more lands than you, you may put a land card from your hand onto the battlefield.

Monk Class

(Gain the next level as a sorcery to add its ability.)
The second spell you cast each turn costs {1} less to cast.
{W}{U}: Level 2
When this Class becomes level 2, return up to one target nonland permanent to its owner's hand.
{1}{W}{U}: Level 3
At the beginning of your upkeep, exile the top card of your library. For as long as it remains exiled, it has "You may cast this card from exile as long as you've cast another spell this turn."

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Swift End

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)

Murderous Rider

Lifelink
When this creature dies, put it on the bottom of its owner's library.

Murderous Rider // Swift End

Champions from Beyond

When this enchantment enters, create X 1/1 colorless Hero creature tokens.
Light Party — Whenever you attack with four or more creatures, scry 2, then draw a card.
Full Party — Whenever you attack with eight or more creatures, those creatures get +4/+4 until end of turn.

Split Up

Choose one —
• Destroy all tapped creatures.
• Destroy all untapped creatures.

Swamp

Lyse Hext

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Noncreature spells you cast cost {1} less to cast.
As long as you've cast two or more noncreature spells this turn, Lyse Hext has double strike.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Dancer's Chakrams

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +2/+2, has lifelink and "Other commanders you control get +2/+2 and have lifelink," and is a Performer in addition to its other types.
Krishna — Equip {3}

Unstoppable Plan

At the beginning of your end step, untap all nonland permanents you control.

Sol Ring

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Y'shtola, Night's Blessed

Vigilance
At the beginning of each end step, if a player lost 4 or more life this turn, you draw a card.
Whenever you cast a noncreature spell with mana value 3 or greater, Y'shtola deals 2 damage to each opponent and you gain 2 life.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return this card to the battlefield attached to that creature at the beginning of the next end step.

Desolate Mire

Reassess

Archmage of Runes

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, draw a card.

Catalyst Stone

Flashback costs you pay cost {2} less.
Flashback costs your opponents pay cost {2} more.

Consuming Vapors

Target player sacrifices a creature of their choice. You gain life equal to that creature's toughness.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Arcane Signet

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

Mistvein Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
This artifact enters tapped.
{T}: Add {U} or {B}.

Gilded Lotus

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on this artifact.
At the beginning of each upkeep, put an hour counter on this artifact.
When the twelfth hour counter is put on this artifact, shuffle your hand and graveyard into your library, then draw seven cards. Exile this artifact.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Lotho, Corrupt Shirriff

Whenever a player casts their second spell each turn, you lose 1 life and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Pearl Medallion

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

Fetid Heath

{T}: Add {C}.
{W/B}, {T}: Add {W}{W}, {W}{B}, or {B}{B}.

Dig Through Time

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Look at the top seven cards of your library. Put two of them into your hand and the rest on the bottom of your library in any order.

Solve the Equation

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

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Vindicate

Fandaniel, Telophoroi Ascian

Whenever you cast an instant or sorcery spell, surveil 1.
At the beginning of your end step, each opponent may sacrifice a nontoken creature of their choice. Each opponent who doesn't loses 2 life for each instant and sorcery card in your graveyard.

Promise of Loyalty

Each player puts a vow counter on a creature they control and sacrifices the rest. Each of those creatures can't attack you or planeswalkers you control for as long as it has a vow counter on it.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Contaminated Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle.
Cycling {W}{U}{B} ({W}{U}{B}, Discard this card: Draw a card.)

Blue Mage's Cane

Job select
Equipped creature gets +0/+2, is a Wizard in addition to its other types, and has "Whenever this creature attacks, exile up to one target instant or sorcery card from defending player's graveyard. If you do, copy it. You may cast the copy by paying {3} rather than paying its mana cost."
Spirit of the Whalaqee — Equip {2}

Observed Stasis

Flash
Enchant creature an opponent controls
When this Aura enters, remove enchanted creature from combat. Then draw a card for each tapped creature its controller controls.
Enchanted creature loses all abilities and can't attack or block.

G'raha Tia, Scion Reborn

Lifelink
Throw Wide the Gates — Whenever you cast a noncreature spell, you may pay X life, where X is that spell's mana value. If you do, create a 1/1 colorless Hero creature token and put X +1/+1 counters on it. Do this only once each turn.

Blessed Reincarnation

Exile target creature an opponent controls. That player reveals cards from the top of their library until a creature card is revealed. The player puts that card onto the battlefield, then shuffles the rest into their library.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Hermes, Overseer of Elpis

Whenever you cast a noncreature spell, create a 1/1 blue Bird creature token with flying and vigilance.
Whenever you attack with one or more Birds, scry 2.

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Alisaie Leveilleur

Partner with Alphinaud Leveilleur (When this creature enters, target player may put Alphinaud Leveilleur into their hand from their library, then shuffle.)
First strike
Dualcast — The second spell you cast each turn costs {2} less to cast.

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.)

Fabricate

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

Papalymo Totolymo

Whenever you cast a noncreature spell, Papalymo Totolymo deals 1 damage to each opponent and you gain 1 life.
{4}, {T}, Sacrifice Papalymo Totolymo: Each opponent who lost life this turn sacrifices a creature with the greatest power among creatures they control.

Seize the Secrets

This spell costs {1} less to cast if you've committed a crime this turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)
Draw two cards.

Thancred Waters

Flash
Royal Guard — When Thancred Waters enters, another target legendary permanent you control gains indestructible for as long as you control Thancred Waters.
Whenever you cast a noncreature spell, Thancred Waters gains indestructible until end of turn.

Sublime Epiphany

Choose one or more —
• Counter target spell.
• Counter target activated or triggered ability.
• Return target nonland permanent to its owner's hand.
• Create a token that's a copy of target creature you control.
• Target player draws a card.

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Lier, Disciple of the Drowned

Spells can't be countered.
Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Sunken Hollow

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

Ghoulish Impetus

Enchant creature
Enchanted creature gets +1/+1, has deathtouch, and is goaded.
When enchanted creature dies, return this card to the battlefield at the beginning of the next end step.

Cut a Deal

Each opponent draws a card, then you draw a card for each opponent who drew a card this way.

Void Rend

This spell can't be countered.
Destroy target nonland permanent.

Island

Evolving Wilds

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

Ojutai's Breath

Tap target creature. It doesn't untap during its controller's next untap step.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Transpose

Draw a card, then discard a card. You lose 1 life. If this spell was cast from your hand, create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Gentleman's Rise

Create a 2/2 black Zombie creature token. (Then exile this card. You may cast the creature later from exile.)

Hildibrand Manderville

Creature tokens you control get +1/+1.
When Hildibrand Manderville dies, you may cast it from your graveyard as an Adventure until the end of your next turn.

Hildibrand Manderville // Gentleman's Rise

Love

Skyclave Apparition

When this creature enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less.
When this creature leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card.

Temple of Enlightenment

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {U}.

Lethal Scheme

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy target creature or planeswalker. Each creature that convoked this spell connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

Urianger Augurelt

Whenever you play a land from exile or cast a spell from exile, you gain 2 life.
Draw Arcanum — {T}: Look at the top card of your library. You may exile it face down.
Play Arcanum — {T}: Until end of turn, you may play cards exiled with Urianger Augurelt. Spells you cast this way cost {2} less to cast.

Darkwater Catacombs

Plains

Torrential Gearhulk

Flash
When this creature enters, you may cast target instant card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Caetus, Sea Tyrant of Segovia

Noncreature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a noncreature spell pays for {1} or one mana of that creature's color.)
At the beginning of your end step, untap up to four target creatures.

Invasion of Segovia

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, create two 1/1 blue Kraken creature tokens with trample.

Invasion of Segovia // Caetus, Sea Tyrant of Segovia

White Auracite

When this artifact enters, exile target nonland permanent an opponent controls until this artifact leaves the battlefield.
{T}: Add {W}.

Sapphire Medallion

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

Isolated Chapel

This land enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Amphibian Downpour

Flash
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.

Emet-Selch of the Third Seat

Spells you cast from your graveyard cost {2} less to cast.
Whenever one or more opponents lose life, you may cast target instant or sorcery card from your graveyard. If that spell would be put into your graveyard, exile it instead. Do this only once each turn.

Rammas Echor, Ancient Shield

Whenever you cast your second spell each turn, draw a card, then create a 0/3 white Wall creature token with defender.
At the beginning of combat on your turn, creatures you control with defender gain exalted until end of turn. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Muraganda Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {T}: Add {C}{C}.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Quantum Misalignment

Create a token that's a copy of target creature you control, except it isn't legendary.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Cleansing Nova

Choose one —
• Destroy all creatures.
• Destroy all artifacts and enchantments.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Y'shtola Rhul

At the beginning of your end step, exile target creature you control, then return it to the battlefield under its owner's control. Then if it's the first end step of the turn, there is an additional end step after this step.

Ardbert, Warrior of Darkness

Whenever you cast a white spell, put a +1/+1 counter on each legendary creature you control. They gain vigilance until end of turn.
Whenever you cast a black spell, put a +1/+1 counter on each legendary creature you control. They gain menace until end of turn.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Arcane Melee

Instant and sorcery spells cost {2} less to cast.

Krile Baldesion

Lifelink
Trace Aether — Whenever you cast a noncreature spell, you may return target creature card with mana value equal to that spell's mana value from your graveyard to your hand. Do this only once each turn.

Circle of Power

You draw two cards and you lose 2 life. Create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."
Wizards you control get +1/+0 and gain lifelink until end of turn.

Talisman of Hierarchy

{T}: Add {C}.
{T}: Add {W} or {B}. This artifact deals 1 damage to you.

Hraesvelgr of the First Brood

Flying, vigilance, ward {2}
Shiva's Aid — When Hraesvelgr enters and whenever you cast a noncreature spell, target creature gets +1/+0 until end of turn and can't be blocked this turn.

Charismatic Conqueror

Vigilance
Whenever an artifact or creature an opponent controls enters untapped, they may tap that permanent. If they don't, you create a 1/1 white Vampire creature token with lifelink.