Imperious Mindbreaker

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 Imperious Mindbreaker is paired with another creature, each of those creatures has "Whenever this creature attacks, each opponent mills cards equal to its toughness."

Sol Ring

Illusory Ambusher

Flash (You may cast this spell any time you could cast an instant.)
Whenever Illusory Ambusher is dealt damage, draw that many cards.

Sage's Row Savant

Island

Dreadful as the Storm

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

Explorer's Scope

Whenever equipped creature attacks, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Mocking Sprite

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

Tetsuko Umezawa, Fugitive

Creatures you control with power or toughness 1 or less can't be blocked.

Waterfall Aerialist

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Nebelgast Intruder

Flash
Flying
When Nebelgast Intruder enters, up to one target creature an opponent controls gets -2/-0 until end of turn.

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.

Free the Fae

Mill four cards. Then put an instant, sorcery, or Faerie card from among the milled cards into your hand.

Picklock Prankster

Picklock Prankster // Free the Fae

Goggles of Night

Whenever equipped creature deals combat damage to a player, scry 1, then draw a card. (To scry 1, look at the top card of your library, then you may put that card on the bottom.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Launch Mishap

Counter target creature or planeswalker spell. Create a 1/1 colorless Thopter artifact creature token with flying.

Serpentine Ambush

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

Daring Saboteur

{2}{U}: Daring Saboteur can't be blocked this turn.
Whenever Daring Saboteur deals combat damage to a player, you may draw a card. If you do, discard a card.

Suit Up

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

Crashing Drawbridge

Defender
{T}: Creatures you control gain haste until end of turn.

Arcane Signet

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

Amorphous Axe

Equipped creature gets +3/+0 and is every creature type.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

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.)

Greataxe

Equipped creature gets +4/+0.
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

Murmuring Mystic

Whenever you cast an instant or sorcery spell, create a 1/1 blue Bird Illusion creature token with flying.

Zhalfirin Shapecraft

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

Majestic Metamorphosis

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

Dragon Throne of Tarkir

Equipped creature has defender and "{2}, {T}: Other creatures you control gain trample and get +X/+X until end of turn, where X is this creature's power."
Equip {3}

Scuttletide

{1}, Discard a card: Create a 0/3 blue Crab creature token.
Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

Moonfolk Puzzlemaker

Flying
Whenever Moonfolk Puzzlemaker becomes tapped, scry 1.

Crookclaw Transmuter

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

Scaretiller

Whenever Scaretiller becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.

Desert of the Mindful

Desert of the Mindful enters tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

Digsite Conservator

Sacrifice Digsite Conservator: Exile up to four target cards from a single graveyard. Activate only as a sorcery.
When Digsite Conservator dies, you may pay {4}. If you do, discover 4. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Tandem Lookout

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 Tandem Lookout is paired with another creature, each of those creatures has "Whenever this creature deals damage to an opponent, draw a card."

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Reconnaissance Mission

Whenever a creature you control deals combat damage to a player, you may draw a card.
Cycling {2} ({2}, Discard this card: Draw a card.)

Furtive Analyst

Vigilance
{2}, {T}: Draw a card, then discard a card.

Merfolk Pupil

When Merfolk Pupil enters, draw a card, then discard a card.
{1}{U}, Exile Merfolk Pupil from your graveyard: Draw a card, then discard a card.

Looter il-Kor

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Looter il-Kor deals damage to an opponent, draw a card, then discard a card.

Leather Armor

Equipped creature gets +0/+1 and has ward {1}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {0}. Activate only once each turn.

Screaming Swarm

Flying
Whenever you attack with one or more creatures, target player mills that many cards. (To mill a card, a player puts the top card of their library into their graveyard.)
{2}{U}: Put Screaming Swarm from your graveyard into your library second from the top.

Gateway Sneak

Whenever a Gate you control enters, this creature can't be blocked this turn.
Whenever this creature deals combat damage to a player, draw a card.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Yotian Soldier

Library Larcenist

Whenever Library Larcenist attacks, draw a card.

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.

Parcel Myr

Renowned Weaponsmith

{T}: Add {C}{C}. Spend this mana only to cast artifact spells or activate abilities of artifacts.
{U}, {T}: Search your library for a card named Heart-Piercer Bow or Vial of Dragonfire, reveal it, put it into your hand, then shuffle.

Manakin

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.

Bubble Up

Put target instant or sorcery card from your graveyard on top of your library. (Then exile this card. You may cast the creature later from exile.)

Aquatic Alchemist

Whenever you cast your first instant or sorcery spell each turn, Aquatic Alchemist gets +2/+0 until end of turn.

Aquatic Alchemist // Bubble Up

Twisted Image

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

Hermitic Nautilus

Vigilance
{1}{U}: Hermitic Nautilus gets +3/-3 until end of turn.

Dance of the Skywise

Until end of turn, target creature you control becomes a blue Dragon Illusion with base power and toughness 4/4, loses all abilities, and gains flying.

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.)

Mystic Confluence

Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Feywild Visitor

Commander creatures you own have "Whenever one or more nontoken creatures you control deal combat damage to a player, you create a 1/1 blue Faerie Dragon creature token with flying."

Remote Isle

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

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Forebear's Blade

Equipped creature gets +3/+0 and has vigilance and trample.
Whenever equipped creature dies, attach Forebear's Blade to target creature you control.
Equip {3}

Heart-Piercer Bow

Whenever equipped creature attacks, Heart-Piercer Bow deals 1 damage to target creature defending player controls.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Graceful Adept

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.)

Ghostly Pilferer

Whenever Ghostly Pilferer becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: Ghostly Pilferer can't be blocked this turn.

Gigantoplasm

You may have Gigantoplasm enter as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."