Pendelhaven

{T}: Add {G}.
{T}: Target 1/1 creature gets +1/+2 until end of turn.

Grazilaxx, Illithid Scholar

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Lord of Atlantis

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

Arcane Signet

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

Island

Swamp

Blufferfish

{3}{U}: An opponent tells you a statement about themselves and secretly notes whether it's true or false. You guess which it is. If you guessed correctly, this creature gets +2/+0 and can't be blocked this turn.

Red Herring

Haste
This creature attacks each combat if able.
{2}, Sacrifice this creature: Draw a card.

Counterspell

Numbing Jellyfish

When this creature enters, roll a six-sided die. Target player mills X cards, where X is the result.

Skrelv, Defector Mite

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Skrelv can't block.
{W/P}, {T}: Choose a color. Another target creature you control gains toxic 1 and hexproof from that color until end of turn. It can't be blocked by creatures of that color this turn. ({W/P} can be paid with either {W} or 2 life.)

Barktooth Warbeard

Forest

Charix, the Raging Isle

Spells your opponents cast that target Charix cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

Mountain

Madblind Mountain

({T}: Add {R}.)
This land enters tapped.
{R}, {T}: Shuffle your library. Activate only if you control two or more red permanents.

Commander's Sphere

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

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Command Tower

Jodah, the Unifier

Legendary creatures you control get +X/+X, where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put the rest on the bottom of your library in a random order.

Wishful Merfolk

Defender
{1}{U}: This creature loses defender and becomes a Human until end of turn.

Chromatic Lantern

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

Sol Ring

Food

{2}, {T}, Sacrifice this token: You gain 3 life.

Spatula of the Ages

{4}, {T}, Sacrifice this artifact: You may put a silver-bordered or acorn permanent card from your hand onto the battlefield.

Toski, Bearer of Secrets

This spell can't be countered.
Indestructible
Toski attacks each combat if able.
Whenever a creature you control deals combat damage to a player, draw a card.

Plains

Steelfin Whale

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Whenever an artifact you control enters, untap this creature.

Ramirez DePietro, Pillager

When Ramirez DePietro enters, you lose 2 life and create two Treasure tokens.
Whenever one or more Pirates you control deal combat damage to a player, exile the top card of that player's library. You may cast that card for as long as it remains exiled.

Night's Whisper

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

Inevitable Betrayal

Suspend 3—{1}{U}{U} (Rather than cast this card from your hand, pay {1}{U}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Nuka-Nuke Launcher

Equipped creature gets +3/+0 and has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever equipped creature attacks, until the end of defending player's next turn, that player gets two rad counters whenever they cast a spell.
Equip {3}

Exotic Orchard

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

Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Force of Despair

If it's not your turn, you may exile a black card from your hand rather than pay this spell's mana cost.
Destroy all creatures that entered this turn.

Fearless Swashbuckler

Haste
Vehicles you control have haste.
Whenever you attack, if a Pirate and a Vehicle attacked this combat, draw three cards, then discard two cards.

Rock Lobster

Creatures named Scissors Lizard can't attack or block.

Vault 101: Birthday Party

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 1/1 white Human Soldier creature token and a Food token. (A Food token is an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
II, III — You may put an Aura or Equipment card from your hand or graveyard onto the battlefield. If an Equipment is put onto the battlefield this way, you may attach it to a creature you control.

Curie, Emergent Intelligence

Whenever Curie deals combat damage to a player, draw cards equal to its base power.
{1}{U}, Exile another nontoken artifact creature you control: Curie becomes a copy of the exiled creature, except it has "Whenever this creature deals combat damage to a player, draw cards equal to its base power."