Lost in a Labyrinth

Target creature gets -3/-0 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Dwarven Thaumaturgist

{T}: Switch target creature's power and toughness until end of turn.

Mnemonic Wall

Defender
When Mnemonic Wall enters, you may return target instant or sorcery card from your graveyard to your hand.

Mannichi, the Fevered Dream

{1}{R}: Switch each creature's power and toughness until end of turn.

Unnerving Assault

Creatures your opponents control get -1/-0 until end of turn if {U} was spent to cast this spell, and creatures you control get +1/+0 until end of turn if {R} was spent to cast this spell. (Do both if {U}{R} was spent.)

Dualcaster Mage

Flash
When Dualcaster Mage enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Flowstone Blade

Enchant creature
{R}: Enchanted creature gets +1/-1 until end of turn.

About Face

Switch target creature's power and toughness until end of turn.

Shape Stealer

Whenever Shape Stealer blocks or becomes blocked by a creature, change Shape Stealer's base power and toughness to that creature's power and toughness until end of turn.

Belbe's Armor

{X}, {T}: Target creature gets -X/+X until end of turn.

Rowan Kenrith

+2: During target player's next turn, each creature that player controls attacks if able.
−2: Rowan Kenrith deals 3 damage to each tapped creature target player controls.
−8: Target player gets an emblem with "Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy."
Partner with Will Kenrith
Rowan Kenrith can be your commander.

Pemmin's Aura

Enchant creature
{U}: Untap enchanted creature.
{U}: Enchanted creature gains flying until end of turn.
{U}: Enchanted creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
{1}: Enchanted creature gets +1/-1 or -1/+1 until end of turn.

Melek, Izzet Paragon

Play with the top card of your library revealed.
You may cast instant and sorcery spells from the top of your library.
Whenever you cast an instant or sorcery spell from your library, copy it. You may choose new targets for the copy.

Blinding Spray

Creatures your opponents control get -4/-0 until end of turn.
Draw a card.

Water Servant

{U}: Water Servant gets +1/-1 until end of turn.
{U}: Water Servant gets -1/+1 until end of turn.

Jace's Sanctum

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

Inside Out

Switch target creature's power and toughness until end of turn.
Draw a card.

Scion of Glaciers

{U}: Scion of Glaciers gets +1/-1 until end of turn.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Crookclaw Transmuter

Flash
Flying
When Crookclaw Transmuter enters, switch target creature's power and toughness until end of turn.

Valakut Fireboar

Whenever Valakut Fireboar attacks, switch its power and toughness until end of turn.

Invent

Search your library for an instant card and/or a sorcery card, reveal them, put them into your hand, then shuffle.

Invert

Switch the power and toughness of each of up to two target creatures until end of turn.

Invert // Invent

Strange Inversion

Switch target creature's power and toughness until end of turn.
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.)

Talonrend

Flying
{U/R}: Talonrend gets +1/-1 until end of turn.

Cavern Crawler

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
{R}: Cavern Crawler gets +1/-1 until end of turn.

Downsize

Target creature you don't control gets -4/-0 until end of turn.
Overload {2}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Stream of Unconsciousness

Target creature gets -4/-0 until end of turn. If you control a Wizard, draw a card.

Turn the Tide

Creatures your opponents control get -2/-0 until end of turn.

Nivix Barrier

Flash (You may cast this spell any time you could cast an instant.)
Defender (This creature can't attack.)
When Nivix Barrier enters, target attacking creature gets -4/-0 until end of turn.

Oboro Envoy

Flying
{2}, Return a land you control to its owner's hand: Target creature gets -X/-0 until end of turn, where X is the number of cards in your hand.

Shorecrasher Elemental

{U}: Exile Shorecrasher Elemental, then return it to the battlefield face down under its owner's control.
{1}: Shorecrasher Elemental gets +1/-1 or -1/+1 until end of turn.
Megamorph {4}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Ego Erasure

Changeling (This card is every creature type.)
Creatures target player controls get -2/-0 and lose all creature types until end of turn.

Schismotivate

Target creature gets +4/+0 until end of turn. Another target creature gets -4/-0 until end of turn.

Roilmage's Trick

Converge — Creatures your opponents control get -X/-0 until end of turn, where X is the number of colors of mana spent to cast this spell.
Draw a card.

Fluxcharger

Flying
Whenever you cast an instant or sorcery spell, you may switch Fluxcharger's power and toughness until end of turn.

Meishin, the Mind Cage

All creatures get -X/-0, where X is the number of cards in your hand.

Pull from the Deep

Return up to one target instant card and up to one target sorcery card from your graveyard to your hand. Exile Pull from the Deep.

Cumber Stone

Creatures your opponents control get -1/-0.

Twisted Image

Reliquary Tower

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

Frostburn Weird

{U/R}: Frostburn Weird gets +1/-1 until end of turn.

Crag Puca

{U/R}: Switch Crag Puca's power and toughness until end of turn.

Hysterical Blindness

Creatures your opponents control get -4/-0 until end of turn.

Ironclaw Curse

Enchant creature
Enchanted creature gets -0/-1.
Enchanted creature can't block creatures with power equal to or greater than the enchanted creature's toughness.

Arcane Melee

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

Call to Mind

Return target instant or sorcery card from your graveyard to your hand.

Agoraphobia

Enchant creature
Enchanted creature gets -5/-0.
{2}{U}: Return Agoraphobia to its owner's hand.

Hydrolash

Attacking creatures get -2/-0 until end of turn.
Draw a card.

Mystic Retrieval

Return target instant or sorcery card from your graveyard to your hand.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flowstone Slide

All creatures get +X/-X until end of turn.

Chemister's Trick

Target creature you don't control gets -2/-0 until end of turn and attacks this turn if able.
Overload {3}{U}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Torchling

{R}: Untap Torchling.
{R}: Target creature blocks Torchling this turn if able.
{R}: Change the target of target spell that targets only Torchling.
{1}: Torchling gets +1/-1 until end of turn.
{1}: Torchling gets -1/+1 until end of turn.

Staff of Zegon

{3}, {T}: Target creature gets -2/-0 until end of turn.

Bewilder

Target creature gets -3/-0 until end of turn.
Draw a card.

Aetherling

{U}: Exile Aetherling. Return it to the battlefield under its owner's control at the beginning of the next end step.
{U}: Aetherling can't be blocked this turn.
{1}: Aetherling gets +1/-1 until end of turn.
{1}: Aetherling gets -1/+1 until end of turn.

Watercourser

{U}: Watercourser gets +1/-1 until end of turn.

Will Kenrith

+2: Until your next turn, up to two target creatures each have base power and toughness 0/3 and lose all abilities.
−2: Target player draws two cards. Until your next turn, instant, sorcery, and planeswalker spells that player casts cost {2} less to cast.
−8: Target player gets an emblem with "Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy."
Partner with Rowan Kenrith
Will Kenrith can be your commander.

Flowstone Mauler

Trample
{R}: Flowstone Mauler gets +1/-1 until end of turn.

Gravitational Shift

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.

Erratic Mutation

Choose target creature. Reveal cards from the top of your library until you reveal a nonland card. That creature gets +X/-X until end of turn, where X is that card's mana value. Put all cards revealed this way on the bottom of your library in any order.