Ideas Unbound

Draw three cards. Discard three cards at the beginning of the next end step.

Sift

Brallin, Skyshark Rider

Partner with Shabraz, the Skyshark (When this creature enters the battlefield, target player may put Shabraz into their hand from their library, then shuffle.)
Whenever you discard a card, put a +1/+1 counter on Brallin, Skyshark Rider and it deals 1 damage to each opponent.
{R}: Target Shark gains trample until end of turn.

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Island

Banisher Priest

When Banisher Priest enters the battlefield, exile target creature an opponent controls until Banisher Priest leaves the battlefield. (That creature returns under its owner's control.)

Flip the Switch

Counter target spell unless its controller pays {4}. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Arcane Encyclopedia

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Shabraz, the Skyshark

Partner with Brallin, Skyshark Rider
Flying
Whenever you draw a card, put a +1/+1 counter on Shabraz, the Skyshark and you gain 1 life.
{W/U}: Target Human gains flying until end of turn.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Mammoth Umbra

Enchant creature
Enchanted creature gets +3/+3 and has vigilance.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Faithless Salvaging

Discard a card, then draw a card.
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.)

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Mystic Meditation

Draw three cards. Then discard two cards unless you discard a creature card.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Blast of Genius

Choose any target. Draw three cards, then discard a card. Blast of Genius deals damage equal to the discarded card's mana value to that permanent or player.

Thrilling Discovery

You gain 2 life. Then you may discard two cards. If you do, draw three cards.

Banishing Light

When Banishing Light enters the battlefield, exile target nonland permanent an opponent controls until Banishing Light leaves the battlefield.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Tricks of the Trade

Enchant creature
Enchanted creature gets +2/+0 and can't be blocked.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

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.)

Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters the battlefield, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Crush

Traveler's Cloak

Enchant creature
As Traveler's Cloak enters the battlefield, choose a land type.
When Traveler's Cloak enters the battlefield, draw a card.
Enchanted creature has landwalk of the chosen type. (It can't be blocked as long as defending player controls a land of that type.)

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Bag of Holding

Whenever you discard a card, exile that card from your graveyard.
{2}, {T}: Draw a card, then discard a card.
{4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.

Loch Dragon

Flying
Whenever Loch Dragon enters the battlefield or attacks, you may discard a card. If you do, draw a card.

Azorius Signet

Izzet Signet

Academic Dispute

Target creature blocks this turn if able. You may have it gain reach until end of turn.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Dawnbringer Cleric

When Dawnbringer Cleric enters the battlefield, choose one —
• Cure Wounds — You gain 2 life.
• Dispel Magic — Destroy target enchantment.
• Gentle Repose — Exile target card from a graveyard.

Boros Signet

Rain of Revelation

Sol Ring

Academy Raider

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever Academy Raider deals combat damage to a player, you may discard a card. If you do, draw a card.

Cloak of Mists

Enchant creature
Enchanted creature can't be blocked.

Narset of the Ancient Way

+1: You gain 2 life. Add {U}, {R}, or {W}. Spend this mana only to cast a noncreature spell.
−2: Draw a card, then you may discard a card. When you discard a nonland card this way, Narset of the Ancient Way deals damage equal to that card's mana value to target creature or planeswalker.
−6: You get an emblem with "Whenever you cast a noncreature spell, this emblem deals 2 damage to any target."

Deny the Divine

Counter target creature or enchantment spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Mesmeric Glare

Counter target spell with mana value 3 or less. (Then exile this card. You may cast the creature later from exile.)

Hypnotic Sprite

Hypnotic Sprite // Mesmeric Glare

Faithful Mending

You gain 2 life, draw two cards, then discard two cards.
Flashback {1}{W}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Mistford River Turtle

Whenever Mistford River Turtle attacks, another target attacking non-Human creature can't be blocked this turn.

Burning-Tree Vandal

Riot (This creature enters the battlefield with your choice of a +1/+1 counter or haste.)
Whenever Burning-Tree Vandal attacks, you may discard a card. If you do, draw a card.

Drake Umbra

Enchant creature
Enchanted creature gets +3/+3 and has flying.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Skeleton Key

Equipped creature has skulk. (It can't be blocked by creatures with greater power.)
Whenever equipped creature deals combat damage to a player, you may draw a card. If you do, discard a card.
Equip {2}

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Glacial Floodplain

({T}: Add {W} or {U}.)
Glacial Floodplain enters the battlefield tapped.

Pore Over the Pages

Draw three cards, untap up to two lands, then discard a card.

Invisibility

Enchant creature
Enchanted creature can't be blocked except by Walls.

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Wandering Champion

Whenever Wandering Champion deals combat damage to a player, if you control a blue or red permanent, you may discard a card. If you do, draw a card.

Immersturm Raider

When Immersturm Raider enters the battlefield, you may discard a card. If you do, draw a card.

Volatile Fjord

({T}: Add {U} or {R}.)
Volatile Fjord enters the battlefield tapped.

Break Ties

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.
Reinforce 1—{W} ({W}, Discard this card: Put a +1/+1 counter on target creature.)

Mountain

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Blade Banish

Exile target creature with power 4 or greater.

Alpine Meadow

({T}: Add {R} or {W}.)
Alpine Meadow enters the battlefield tapped.

Plains

Gutter Shortcut

Enchant creature
Enchanted creature can't be blocked as long as it's attacking alone.
If Gutter Shortcut would be put into a graveyard from anywhere, exile it instead.

Gutter Skulker

Gutter Skulker can't be blocked as long as it's attacking alone.
Disturb {3}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Gutter Skulker // Gutter Shortcut

Seeker

Enchant creature
Enchanted creature can't be blocked except by artifact creatures and/or white creatures.

Battlefield Scavenger

You may exert Battlefield Scavenger as it attacks. (It won't untap during your next untap step.)
Whenever you exert a creature, you may discard a card. If you do, draw a card.

Furyblade Vampire

Trample
At the beginning of combat on your turn, you may discard a card. If you do, Furyblade Vampire gets +3/+0 until end of turn.

Arcane Signet

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

Temporal Isolation

Flash
Enchant creature
Enchanted creature has shadow. (It can block or be blocked by only creatures with shadow.)
Prevent all damage that would be dealt by enchanted creature.

Akroma's Vengeance

Destroy all artifacts, creatures, and enchantments.
Cycling {3} ({3}, Discard this card: Draw a card.)