Grafted Identity

As an additional cost to cast this spell, sacrifice a creature.
Enchant creature
You control enchanted creature.
Enchanted creature gets +1/+1.

Skyclave Squid

Defender
Landfall — Whenever a land you control enters, Skyclave Squid can attack this turn as though it didn't have defender.

Mind Stone

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

Nadir Kraken

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on Nadir Kraken and create a 1/1 blue Tentacle creature token.

Kiora Bests the Sea God

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create an 8/8 blue Kraken creature token with hexproof.
II — Tap all nonland permanents target opponent controls. They don't untap during their controller's next untap step.
III — Gain control of target permanent an opponent controls. Untap it.

Mind Control

Enchant creature
You control enchanted creature.

Clinging Anemones

Defender
Evolve (Whenever a creature enters under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Dominate

Gain control of target creature with mana value X or less.

Octavia, Living Thesis

This spell costs {8} less to cast if you have eight or more instant and/or sorcery cards in your graveyard.
Ward {8}
Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature has base power and toughness 8/8 until end of turn.

Sol Ring

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Persuasion

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
You control enchanted creature.

Arcane Signet

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

Glowing Anemone

When Glowing Anemone enters, you may return target land to its owner's hand.

Kefnet's Last Word

Gain control of target artifact, creature, or enchantment. Lands you control don't untap during your next untap step.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Acquisition Octopus

Whenever Acquisition Octopus or equipped creature deals combat damage to a player, draw a card.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Avizoa

Flying
{0}: Avizoa gets +2/+2 until end of turn. You skip your next untap step. Activate only once each turn.

Legacy's Allure

At the beginning of your upkeep, you may put a treasure counter on Legacy's Allure.
Sacrifice Legacy's Allure: Gain control of target creature with power less than or equal to the number of treasure counters on Legacy's Allure. (This effect lasts indefinitely.)

Domestication

Enchant creature
You control enchanted creature.
At the beginning of your end step, if enchanted creature's power is 4 or greater, sacrifice Domestication.

Island

Mirrormade

You may have Mirrormade enter as a copy of any artifact or enchantment on the battlefield.

Gulf Squid

When Gulf Squid enters, tap all lands target player controls.

Threads of Disloyalty

Enchant creature with mana value 2 or less
You control enchanted creature.

Control Magic

Sea-Dasher Octopus

Mutate {1}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Entrancing Melody

Gain control of target creature with mana value X.

Tempted by the Oriq

For each opponent, gain control of up to one target creature or planeswalker that player controls with mana value 3 or less.

Man-o'-War

When Man-o'-War enters, return target creature to its owner's hand.

Estrid's Invocation

You may have Estrid's Invocation enter as a copy of an enchantment you control, except it has "At the beginning of your upkeep, you may exile this enchantment. If you do, return it to the battlefield under its owner's control."

Corrupted Conscience

Enchant creature
You control enchanted creature.
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Chamber of Manipulation

Enchant land
Enchanted land has "{T}, Discard a card: Gain control of target creature until end of turn."

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Fylamarid

Flying
Fylamarid can't be blocked by blue creatures.
{U}: Target creature becomes blue until end of turn.

Mesmerizing Benthid

When Mesmerizing Benthid enters, create two 0/2 blue Illusion creature tokens with "Whenever this creature blocks a creature, that creature doesn't untap during its controller's next untap step."
Mesmerizing Benthid has hexproof as long as you control an Illusion.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Aethersnatch

Gain control of target spell. You may choose new targets for it. (If that spell becomes a permanent, it enters under your control.)

Ray of Command

Untap target creature an opponent controls and gain control of it until end of turn. That creature gains haste until end of turn. When you lose control of the creature, tap it.

Illusory Gains

Enchant creature
You control enchanted creature.
Whenever a creature an opponent controls enters, attach Illusory Gains to that creature.

Lorthos, the Tidemaker

Whenever Lorthos, the Tidemaker attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.

Sealock Monster

Sealock Monster can't attack unless defending player controls an Island.
{5}{U}{U}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Sealock Monster becomes monstrous, target land becomes an Island in addition to its other types.

Octoprophet

When Octoprophet enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on Oneirophage.

Enthralling Hold

Enchant creature
You can't choose an untapped creature as this spell's target as you cast it.
You control enchanted creature.

Guard Gomazoa

Defender, flying
Prevent all combat damage that would be dealt to Guard Gomazoa.

Vedalken Shackles

You may choose not to untap Vedalken Shackles during your untap step.
{2}, {T}: Gain control of target creature with power less than or equal to the number of Islands you control for as long as Vedalken Shackles remains tapped.

Abduction

Enchant creature
When Abduction enters, untap enchanted creature.
You control enchanted creature.
When enchanted creature dies, return that card to the battlefield under its owner's control.

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters tapped unless you control three or more other Islands.
When Mystic Sanctuary enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Esperzoa

Flying
At the beginning of your upkeep, return an artifact you control to its owner's hand.

Steal Artifact

Enchant artifact
You control enchanted artifact.

Lullmage's Domination

This spell costs {3} less to cast if it targets a creature whose controller has eight or more cards in their graveyard.
Gain control of target creature with mana value X.

Counterspell

Godhunter Octopus

Godhunter Octopus can't attack unless defending player controls an enchantment or an enchanted permanent.

The Reality Chip

You may look at the top card of your library any time.
As long as The Reality Chip is attached to a creature, you may play lands and cast spells from the top of your library.
Reconfigure {2}{U} ({2}{U}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Sand Squid

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
You may choose not to untap Sand Squid during your untap step.
{T}: Tap target creature. That creature doesn't untap during its controller's untap step for as long as Sand Squid remains tapped.

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Glimmerbell

Invoke the Winds

Gain control of target artifact or creature. Untap it.

Welcome to the Fold

Madness {X}{U}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Gain control of target creature if its toughness is 2 or less. If this spell's madness cost was paid, instead gain control of that creature if its toughness is X or less.

Gomazoa

Defender, flying
{T}: Put Gomazoa and each creature it's blocking on top of their owners' libraries, then those players shuffle.

Leyline of Anticipation

If Leyline of Anticipation is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Dormant Gomazoa

Flying
Dormant Gomazoa enters tapped.
Dormant Gomazoa doesn't untap during your untap step.
Whenever you become the target of a spell, you may untap Dormant Gomazoa.

Elder Deep-Fiend

Flash
Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.