Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

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.")

Kozilek's Channeler

Water Wings

Until end of turn, target creature you control has base power and toughness 4/4 and gains flying and hexproof. (It can't be the target of spells or abilities your opponents control.)

Suit Up

Until end of turn, target creature or Vehicle becomes an artifact creature with base power and toughness 4/5.
Draw a card.

Dreadful as the Storm

Target creature has base power and toughness 5/5 until end of turn. The Ring tempts you.

Quick Study

Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Sky Diamond

Aarakocra Sneak

Flying
When Aarakocra Sneak enters, you take the initiative.

Aspirant's Ascent

Until end of turn, target creature gets +1/+3 and gains flying and toxic 1. (Players dealt combat damage by that creature also get a poison counter.)

Remote Isle

Remote Isle enters tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Elgaud Shieldmate

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Elgaud Shieldmate is paired with another creature, both creatures have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Fractured Powerstone

{T}: Add {C}.
{T}: Roll the planar die. Activate only as a sorcery.

Keep Safe

Counter target spell that targets a permanent you control.
Draw a card.

Sisay's Ring

Stone Retrieval Unit

When Stone Retrieval Unit enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Counterspell

Staunch Throneguard

Vigilance
When Staunch Throneguard enters, you become the monarch.

Guardian Idol

Guardian Idol enters tapped.
{T}: Add {C}.
{2}: Guardian Idol becomes a 2/2 Golem artifact creature until end of turn.

Behind the Mask

As an additional cost to cast this spell, you may collect evidence 6. (Exile cards with total mana value 6 or greater from your graveyard.)
Until end of turn, target artifact or creature becomes an artifact creature with base power and toughness 4/3. If evidence was collected, it has base power and toughness 1/1 until end of turn instead.

Wings of Velis Vel

Changeling (This card is every creature type.)
Until end of turn, target creature has base power and toughness 4/4, gains all creature types, and gains flying.

Stern Lesson

Draw two cards, then discard a card. Create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ornithopter of Paradise

Negate

Strider Harness

Equipped creature gets +1/+1 and has haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Startling Development

Until end of turn, target creature becomes a blue Serpent with base power and toughness 4/4.
Cycling {1} ({1}, Discard this card: Draw a card.)

Displace

Exile up to two target creatures you control, then return those cards to the battlefield under their owner's control.

Tymora's Invoker

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Experimental Augury

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. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Majestic Metamorphosis

Until end of turn, target artifact or creature becomes a 4/4 Angel artifact creature and gains flying.
Draw a card.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Peregrine Drake

Flying
When Peregrine Drake enters, untap up to five lands.

Combat Courier

{2}, Sacrifice Combat Courier: Draw a card.
Unearth {U} ({U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Koilos Roc

Flash
Flying
When Koilos Roc enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Case the Joint

Draw two cards, then look at the top card of each player's library.

Thought Vessel

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

Relic's Roar

Until end of turn, target artifact or creature becomes a Dinosaur artifact creature with base power and toughness 4/3 in addition to its other types.

Taigam's Strike

Target creature gets +2/+0 until end of turn and can't be blocked this turn.
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.)

Island

Serpentine Ambush

Until end of turn, target creature becomes a blue Serpent with base power and toughness 5/5.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Zhalfirin Shapecraft

Target creature has base power and toughness 4/3 until end of turn.
Draw a card.

Cradle of Safety

Flash
Enchant creature you control
When Cradle of Safety enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Coastal Bulwark

Defender
Coastal Bulwark gets +2/+0 as long as you control an Island.
{2}, {T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Automated Artificer

{T}: Add {C}. Spend this mana only to activate an ability or cast an artifact spell.

Amass the Components

Draw three cards, then put a card from your hand on the bottom of your library.

Mordenkainen's Polymorph

Until end of turn, target creature becomes a Dragon with base power and toughness 4/4 and gains flying. (It loses all other creature types.)

Steady Progress

Phantasmal Form

Until end of turn, up to two target creatures each have base power and toughness 3/3, gain flying, and become blue Illusions in addition to their other colors and types.
Draw a card.

Trailblazer's Torch

When Trailblazer's Torch enters, you take the initiative.
Whenever equipped creature becomes blocked, it deals 2 damage to each creature blocking it.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Scattered Thoughts

Look at the top four cards of your library. Put two of those cards into your hand and the rest into your graveyard.

Third Path Savant

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Blighted Agent can't be blocked.

Fellwar Stone

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

Sea Scryer

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Mesmerizing Dose

Enchant creature
When Mesmerizing Dose enters, tap enchanted creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Enchanted creature doesn't untap during its controller's untap step.