Lodestone Bauble

{1}, {T}, Sacrifice Lodestone Bauble: Put up to four target basic land cards from a player's graveyard on top of their library in any order. That player draws a card at the beginning of the next turn's upkeep.

Robe of the Archmagi

Whenever equipped creature deals combat damage to a player, you draw that many cards.
Equip {4}
Equip Shaman, Warlock, or Wizard {1}

Vexing Bauble

Whenever a player casts a spell, if no mana was spent to cast it, counter that spell.
{1}, {T}, Sacrifice Vexing Bauble: Draw a card.

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When Thieving Skydiver enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to Thieving Skydiver.

Seat of the Synod

Seafloor Oracle

Whenever a Merfolk you control deals combat damage to a player, draw a card.

Forensic Researcher

{T}: Untap another target permanent you control.
{T}, Collect evidence 3: Tap target creature you don't control. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)

Chromatic Sphere

{1}, {T}, Sacrifice Chromatic Sphere: Add one mana of any color. Draw a card.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on Bloodline Pretender.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Arcane Signet

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

Thada Adel, Acquisitor

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Thada Adel, Acquisitor deals combat damage to a player, search that player's library for an artifact card and exile it. Then that player shuffles. Until end of turn, you may play that card.

Chromatic Star

{1}, {T}, Sacrifice Chromatic Star: Add one mana of any color.
When Chromatic Star is put into a graveyard from the battlefield, draw a card.

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Trickster's Talisman

Invoke Duplicity — Equipped creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, you may sacrifice Trickster's Talisman. If you do, create a token that's a copy of this creature."
Equip {2}

Library Larcenist

Whenever Library Larcenist attacks, draw a card.

Vedalken Orrery

You may cast spells as though they had flash.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have Phyrexian Metamorph enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

Triton Shorestalker

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

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.

Mask of the Schemer

Whenever equipped creature deals combat damage to a player, it connives X, where X is the amount of damage it dealt to that player. (Draw X cards, then discard X cards. Put a +1/+1 counter on that creature for each nonland card discarded this way.)
Equip {2}

Mystery Key

When equipped creature deals combat damage to a player, sacrifice Mystery Key. If you do, draw three cards.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Etherium Sculptor

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

Sol Ring

Kiora, the Rising Tide

When Kiora enters, draw two cards, then discard two cards.
Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus creature token.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Island

Merfolk Windrobber

Flying
Whenever Merfolk Windrobber deals combat damage to a player, that player mills a card. (They put the top card of their library into their graveyard.)
Sacrifice Merfolk Windrobber: Draw a card. Activate only if an opponent has eight or more cards in their graveyard.

Aether Spellbomb

{U}, Sacrifice Aether Spellbomb: Return target creature to its owner's hand.
{1}, Sacrifice Aether Spellbomb: Draw a card.

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on Midnight Clock.
At the beginning of each upkeep, put an hour counter on Midnight Clock.
When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Tempest Caller

When Tempest Caller enters, tap all creatures target opponent controls.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Lantern of Insight

Players play with the top card of their libraries revealed.
{T}, Sacrifice Lantern of Insight: Target player shuffles.

Benthic Criminologists

Whenever Benthic Criminologists enters or attacks, you may sacrifice an artifact. If you do, draw a card.

Merrow Commerce

At the beginning of your end step, untap all Merfolk you control.

Harbinger of the Seas

Inundate

Return all nonblue creatures to their owners' hands.

Implement of Examination

{U}, Sacrifice Implement of Examination: Draw a card.
When Implement of Examination is put into a graveyard from the battlefield, draw a card.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: Draw 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.

Deeproot Pilgrimage

Whenever one or more nontoken Merfolk you control become tapped, create a 1/1 blue Merfolk creature token with hexproof.

Moonsilver Key

{1}, {T}, Sacrifice Moonsilver Key: Search your library for an artifact card with a mana ability or a basic land card, reveal it, put it into your hand, then shuffle.

Sky Diamond

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

Counterspell

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Waterwind Scout

Flying
When Waterwind Scout enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Merfolk Sovereign

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Encroaching Mycosynth

Nonland permanents you control are artifacts in addition to their other types. The same is true for permanent spells you control and nonland permanent cards you own that aren't on the battlefield.

River Herald Scout

When River Herald Scout enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Candy Trail

When Candy Trail enters, scry 2.
{2}, {T}, Sacrifice Candy Trail: You gain 3 life and draw a card.

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Svyelun of Sea and Sky

Svyelun of Sea and Sky has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Conjurer's Bauble

{T}, Sacrifice Conjurer's Bauble: Put up to one target card from your graveyard on the bottom of your library. Draw a card.

Thassa's Bounty

Draw three cards. Target player mills three cards.

Umara Skyfalls

Umara Skyfalls enters tapped.
{T}: Add {U}.

Umara Wizard

Whenever you cast an instant, sorcery, or Wizard spell, Umara Wizard gains flying until end of turn.

Umara Wizard // Umara Skyfalls

Crystal Skull, Isu Spyglass

You may look at the top card of your library any time.
You may play historic lands and cast historic spells from the top of your library. (Artifacts, legendaries, and Sagas are historic.)
{T}: Add {U}.

Machine God's Effigy

You may have Machine God's Effigy enter as a copy of any creature on the battlefield, except it's an artifact and it has "{T}: Add {U}." (It's not a creature.)
{T}: Add {U}.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.