Mesmeric Sliver

All Slivers have "When this permanent enters, you may fateseal 1." (To fateseal 1, its controller looks at the top card of an opponent's library, then they may put that card on the bottom of that library.)

Peer Pressure

Choose a creature type. If you control more creatures of that type than each other player, you gain control of all creatures of that type. (This effect lasts indefinitely.)

Avian Changeling

Changeling (This card is every creature type.)
Flying

Dance of the Tumbleweeds

Spree (Choose one or more additional costs.)
+ {1} — Search your library for a basic land card or a Desert card, put it onto the battlefield, then shuffle.
+ {3} — Create an X/X green Elemental creature token, where X is the number of lands you control.

Moritte of the Frost

Changeling (This card is every creature type.)
You may have Moritte enter as a copy of a permanent you control, except it's legendary and snow in addition to its other types and, if it's a creature, it enters with two additional +1/+1 counters on it and has changeling.

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Impostor of the Sixth Pride

Changeling (This card is every creature type.)

King of the Pride

Wildsize

Target creature gets +2/+2 and gains trample until end of turn.
Draw a card.

Have

Bloodline Pretender

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

Littjara Kinseekers

Changeling (This card is every creature type.)
When this creature enters, if you control three or more creatures that share a creature type, put a +1/+1 counter on this creature, then scry 1.

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Gemhide Sliver

All Slivers have "{T}: Add one mana of any color."

Wayfarer's Bauble

{2}, {T}, Sacrifice this artifact: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Lonely Arroyo

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {W} or {U}.

Krosan Verge

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for a Forest card and a Plains card, put them onto the battlefield tapped, then shuffle.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Harmonic Sliver

All Slivers have "When this permanent enters, destroy target artifact or enchantment."

Birthing Boughs

{4}, {T}: Create a 2/2 colorless Shapeshifter creature token with changeling. (It is every creature type.)

The Bears of Littjara

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 2/2 blue Shapeshifter creature token with changeling.
II — Any number of target Shapeshifter creatures you control have base power and toughness 4/4.
III — Choose up to one target creature or planeswalker. Each creature with power 4 or greater you control deals damage equal to its power to that permanent.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Invigorate

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life.
Target creature gets +4/+4 until end of turn.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Seafloor Oracle

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

Woodland Changeling

Airborne Aid

Draw a card for each Bird on the battlefield.

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.

Sophia, Dogged Detective

When Sophia enters, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

Mirage Mirror

{2}: This artifact becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Temple of Plenty

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {G} or {W}.

Tangled Islet

({T}: Add {G} or {U}.)
This land enters tapped.

Bonescythe Sliver

Sliver creatures you control have double strike. (They deal both first-strike and regular combat damage.)

Hakbal of the Surging Soul

At the beginning of combat on your turn, each Merfolk creature you control 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 the exploring creature, then put the card back or put it into your graveyard.)
Whenever Hakbal attacks, you may put a land card from your hand onto the battlefield. If you don't, draw a card.

Kindred Boon

As this enchantment enters, choose a creature type.
{1}{W}: Put a divinity counter on target creature you control of the chosen type.
Each creature you control with a divinity counter on it has indestructible.

Tanglepool Bridge

This land enters tapped.
Indestructible
{T}: Add {G} or {U}.

Lush Oasis

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {G} or {U}.

Fortified Beachhead

As this land enters, you may reveal a Soldier card from your hand. This land enters tapped unless you revealed a Soldier card this way or you control a Soldier.
{T}: Add {W} or {U}.
{5}, {T}: Soldiers you control get +1/+1 until end of turn.

Spelunking

When this enchantment enters, draw a card, then you may put a land card from your hand onto the battlefield. If you put a Cave onto the battlefield this way, you gain 4 life.
Lands you control enter untapped.

Razortide Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {U}.

Guardian Gladewalker

Changeling (This card is every creature type.)
When this creature enters, put a +1/+1 counter on target creature.

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.

Unclaimed Territory

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Arcane Signet

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

Creosote Heath

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {G} or {W}.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Behold the Multiverse

Scry 2, then draw two cards.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Brokers Hideout

When this land enters, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Talisman of Curiosity

{T}: Add {C}.
{T}: Add {G} or {U}. This artifact deals 1 damage to you.

Kumena, Tyrant of Orazca

Tap another untapped Merfolk you control: Kumena can't be blocked this turn.
Tap three untapped Merfolk you control: Draw a card.
Tap five untapped Merfolk you control: Put a +1/+1 counter on each Merfolk you control.

Universal Automaton

Ally Encampment

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Ally spell.
{1}, {T}, Sacrifice this land: Return target Ally you control to its owner's hand.

Seshiro the Anointed

Other Snake creatures you control get +2/+2.
Whenever a Snake you control deals combat damage to a player, you may draw a card.

Sol Ring

Temple of Mystery

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {G} or {U}.

Chameleon Colossus

Changeling (This card is every creature type.)
Protection from black
{2}{G}{G}: This creature gets +X/+X until end of turn, where X is its power.

Wood Elves

When this creature enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Masked Vandal

Changeling (This card is every creature type.)
When this creature enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

Valiant Changeling

This spell costs {1} less to cast for each creature type among creatures you control. This effect can't reduce the amount of mana this spell costs by more than {5}.
Changeling (This card is every creature type.)
Double strike

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: This creature gains flying until end of turn.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Heron's Grace Champion

Flash
Lifelink
When this creature enters, other Humans you control get +1/+1 and gain lifelink until end of turn.

Groundswell

Target creature gets +2/+2 until end of turn.
Landfall — If you had a land enter the battlefield under your control this turn, that creature gets +4/+4 until end of turn instead.

Unsettled Mariner

Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Thornglint Bridge

This land enters tapped.
Indestructible
{T}: Add {G} or {W}.

Drogskol Captain

Flying
Other Spirit creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Katilda and Lier

Whenever you cast a Human spell, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Quick Study

Irregular Cohort

Changeling (This card is every creature type.)
When this creature enters, create a 2/2 colorless Shapeshifter creature token with changeling.

Explore

You may play an additional land this turn.
Draw a card.

Combat Research

Enchant creature
Enchanted creature has "Whenever this creature deals combat damage to a player, draw a card."
As long as enchanted creature is legendary, it gets +1/+1 and has ward {1}. (Whenever enchanted creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Herald of Hoofbeats

Horsemanship (This creature can't be blocked except by creatures with horsemanship.)
Other Knights you control have horsemanship.

Command Tower

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.)

Timberwatch Elf

{T}: Target creature gets +X/+X until end of turn, where X is the number of Elves on the battlefield.

Gilt-Leaf Archdruid

Whenever you cast a Druid spell, you may draw a card.
Tap seven untapped Druids you control: Gain control of all lands target player controls.

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.

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

Risen Reef

Whenever this creature or another Elemental you control enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

The Key to the Vault

Whenever equipped creature deals combat damage to a player, look at that many cards from the top of your library. You may exile a nonland card from among them. Put the rest on the bottom of your library in a random order. You may cast the exiled card without paying its mana cost.
Equip {2}{U}

Shields of Velis Vel

Changeling (This card is every creature type.)
Creatures target player controls get +0/+1 and gain all creature types until end of turn.