Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Deserted Beach

This land enters tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

Tundra

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Soporific Springs

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Sink into Stupor

Return target spell or nonland permanent an opponent controls to its owner's hand.

Sink into Stupor // Soporific Springs

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

New Way Forward

The next time a source of your choice would deal damage to you this turn, prevent that damage. When damage is prevented this way, New Way Forward deals that much damage to that source's controller and you draw that many cards.

Ill-Timed Explosion

Draw two cards. Then you may discard two cards. When you do, Ill-Timed Explosion deals X damage to each creature, where X is the greatest mana value among cards discarded this way.

Wasteland

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target nonbasic land.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Stormcarved Coast

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

Vivi Ornitier

{0}: Add X mana in any combination of {U} and/or {R}, where X is Vivi Ornitier's power. Activate only during your turn and only once each turn.
Whenever you cast a noncreature spell, put a +1/+1 counter on Vivi Ornitier and it deals 1 damage to each opponent.

The Wandering Emperor

Flash
As long as The Wandering Emperor entered this turn, you may activate her loyalty abilities any time you could cast an instant.
+1: Put a +1/+1 counter on up to one target creature. It gains first strike until end of turn.
−1: Create a 2/2 white Samurai creature token with vigilance.
−2: Exile target tapped creature. You gain 2 life.

Hallowed Fountain

({T}: Add {W} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Memory Deluge

Look at the top X cards of your library, where X is the amount of mana spent to cast this spell. Put two of them into your hand and the rest on the bottom of your library in a random order.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Snapcaster Mage

Flash
When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Teferi, Hero of Dominaria

+1: Draw a card. At the beginning of the next end step, untap up to two lands.
−3: Put target nonland permanent into its owner's library third from the top.
−8: You get an emblem with "Whenever you draw a card, exile target permanent an opponent controls."

Expressive Iteration

Look at the top three cards of your library. Put one of them into your hand, put one of them on the bottom of your library, and exile one of them. You may play the exiled card this turn.

Aligned Heart

Flurry — Whenever you cast your second spell each turn, put a rally counter on this enchantment. Then create a 1/1 white Monk creature token with prowess for each rally counter on it. (Whenever you cast a noncreature spell, the token gets +1/+1 until end of turn.)

Pearl Medallion

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

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.")

Elegant Parlor

({T}: Add {R} or {W}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Counterspell

Astrologian's Planisphere

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature is a Wizard in addition to its other types and has "Whenever you cast a noncreature spell and whenever you draw your third card each turn, put a +1/+1 counter on this creature."
Diana — Equip {2}

Arcane Signet

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

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Temple of Epiphany

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 {R}.

Command Tower

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Shiko, Paragon of the Way

Flying, vigilance
When Shiko enters, exile target nonland card with mana value 3 or less from your graveyard. Copy it, then you may cast the copy without paying its mana cost. (A copy of a permanent spell becomes a token.)

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.

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Fellwar Stone

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

Fractured Identity

Exile target nonland permanent. Each player other than its controller creates a token that's a copy of it.

Consign to Memory

Replicate {1} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Counter target triggered ability or colorless spell.

Narset, Parter of Veils

Each opponent can't draw more than one card each turn.
−2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Prismari Command

Choose two —
• Prismari Command deals 2 damage to any target.
• Target player draws two cards, then discards two cards.
• Target player creates a Treasure token.
• Destroy target artifact.

Marsh Flats

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Voice of Victory

Mobilize 2 (Whenever this creature attacks, create two tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)
Your opponents can't cast spells during your turn.

Settle the Wreckage

Exile all attacking creatures target player controls. That player may search their library for that many basic land cards, put those cards onto the battlefield tapped, then shuffle.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Sage of the Skies

When you cast this spell, if you've cast another spell this turn, copy this spell. (The copy becomes a token.)
Flying, lifelink

Bloodstained Mire

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Sunfall

Exile all creatures. Incubate X, where X is the number of creatures exiled this way. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this token." It transforms into a 0/0 Phyrexian artifact creature.)

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Idyllic Tutor

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

Glacial Fortress

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

Sundown Pass

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

Plateau

Teferi, Time Raveler

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Riverpyre Verge

{T}: Add {R}.
{T}: Add {U}. Activate only if you control an Island or a Mountain.

Chandra, Awakened Inferno

This spell can't be countered.
+2: Each opponent gets an emblem with "At the beginning of your upkeep, this emblem deals 1 damage to you."
−3: Chandra deals 3 damage to each non-Elemental creature.
−X: Chandra deals X damage to target creature or planeswalker. If a permanent dealt damage this way would die this turn, exile it instead.

Flamehold Grappler

First strike
When this creature enters, copy the next spell you cast this turn when you cast it. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Cori Mountain Monastery

This land enters tapped unless you control a Plains or an Island.
{T}: Add {R}.
{3}{R}, {T}: Exile the top card of your library. Until the end of your next turn, you may play that 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}.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Wrath of God

Destroy all creatures. They can't be regenerated.

Archmage Emeritus

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

Monastery Mentor

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, create a 1/1 white Monk creature token with prowess.

Reprieve

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

Wooded Foothills

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Sapphire Medallion

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

Rediscover the Way

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
III — Whenever you cast a noncreature spell this turn, target creature you control gains double strike until end of turn.

Jace, the Mind Sculptor

+2: Look at the top card of target player's library. You may put that card on the bottom of that player's library.
0: Draw three cards, then put two cards from your hand on top of your library in any order.
−1: Return target creature to its owner's hand.
−12: Exile all cards from target player's library, then that player shuffles their hand into their library.

Supreme Verdict

This spell can't be countered.
Destroy all creatures.

Esper Sentinel

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

Elspeth, Storm Slayer

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
+1: Create a 1/1 white Soldier creature token.
0: Put a +1/+1 counter on each creature you control. Those creatures gain flying until your next turn.
−3: Destroy target creature an opponent controls with mana value 3 or greater.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Island

Shiko and Narset, Unified

Flying, vigilance
Flurry — Whenever you cast your second spell each turn, copy that spell if it targets a permanent or player, and you may choose new targets for the copy. If you don't copy a spell this way, draw a card.

Sulfur Falls

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

Azcanta, the Sunken Ruin

(Transforms from Search for Azcanta.)
{T}: Add {U}.
{2}{U}, {T}: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Search for Azcanta

At the beginning of your upkeep, surveil 1. Then if you have seven or more cards in your graveyard, you may transform Search for Azcanta. (Look at the top card of your library. You may put that card into your graveyard.)

Search for Azcanta // Azcanta, the Sunken Ruin

Windswept Heath

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Phlage, Titan of Fire's Fury

When Phlage enters, sacrifice it unless it escaped.
Whenever Phlage enters or attacks, it deals 3 damage to any target and you gain 3 life.
Escape—{R}{R}{W}{W}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land 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.

Floodfarm Verge

{T}: Add {W}.
{T}: Add {U}. Activate only if you control a Plains or an Island.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Mystical Tutor

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

Mistrise Village

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn can't be countered.

Frostcliff Siege

As this enchantment enters, choose Jeskai or Temur.
• Jeskai — Whenever one or more creatures you control deal combat damage to a player, draw a card.
• Temur — Creatures you control get +1/+0 and have trample and haste.

Thundering Falls

({T}: Add {U} or {R}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Arid Mesa

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Coil and Catch

Draw three cards, then discard a card. (Then shuffle this card into its owner's library.)

Marang River Regent

Flying
When this creature enters, return up to two other target nonland permanents to their owners' hands.

Marang River Regent // Coil and Catch

Jori En, Ruin Diver

Whenever you cast your second spell each turn, draw a card.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Jeskai Revelation

Return target spell or permanent to its owner's hand. Jeskai Revelation deals 4 damage to any target. Create two 1/1 white Monk creature tokens with prowess. Draw two cards. You gain 4 life.

Elspeth, Sun's Champion

+1: Create three 1/1 white Soldier creature tokens.
−3: Destroy all creatures with power 4 or greater.
−7: You get an emblem with "Creatures you control get +2/+2 and have flying."

Swords to Plowshares

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

Split Up

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