Timestream Navigator

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
{2}{U}{U}, {T}, Put Timestream Navigator on the bottom of its owner's library: Take an extra turn after this one. Activate only if you have the city's blessing.

Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

The Indomitable

Trample
Whenever a creature you control deals combat damage to a player, draw a card.
Crew 3
You may cast The Indomitable from your graveyard as long as you control three or more tapped Pirates and/or Vehicles.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Grim Hireling

Whenever one or more creatures you control deal combat damage to a player, create two Treasure tokens.
{B}, Sacrifice X Treasures: Target creature gets -X/-X until end of turn. Activate only as a sorcery.

Sun Quan, Lord of Wu

Creatures you control have horsemanship. (They can't be blocked except by creatures with horsemanship.)

Enduring Curiosity

Flash
Whenever a creature you control deals combat damage to a player, draw a card.
When Enduring Curiosity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Marionette Master

Fabricate 3 (When this creature enters, put three +1/+1 counters on it or create three 1/1 colorless Servo artifact creature tokens.)
Whenever an artifact you control is put into a graveyard from the battlefield, target opponent loses life equal to Marionette Master's power.

Grasping Scoundrel

Grasping Scoundrel gets +1/+0 as long as it's attacking.

Universal Automaton

Changeling (This card is every creature type.)

Time Sieve

{T}, Sacrifice five artifacts: Take an extra turn after this one.

Curious Obsession

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, you may draw a card."
At the beginning of your end step, if you didn't attack with a creature this turn, sacrifice Curious Obsession.

Oaken Siren

Flying, vigilance
{T}: Add {U}. Spend this mana only to cast an artifact spell or activate an ability of an artifact source.

Worldwalker Helm

If you would create one or more artifact tokens, instead create those tokens plus an additional Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")
{1}{U}, {T}: Create a token that's a copy of target artifact token you control.

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.

Malcolm, Keen-Eyed Navigator

Flying
Whenever one or more Pirates you control deal damage to your opponents, you create a Treasure token for each opponent dealt damage. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Partner (You can have two commanders if both have partner.)

Coastal Piracy

Whenever a creature you control deals combat damage to an opponent, you may draw a card.

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.)

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Curious Inquiry

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, investigate." (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

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.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Haunted One

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Malcolm, Alluring Scoundrel

Flash
Flying
Whenever Malcolm, Alluring Scoundrel deals combat damage to a player, put a chorus counter on it. Draw a card, then discard a card. If there are four or more chorus counters on Malcolm, you may cast the discarded card without paying its mana cost.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Kitesail Larcenist

Flying, ward {1}
When Kitesail Larcenist enters, for each player, choose up to one other target artifact or creature that player controls. For as long as Kitesail Larcenist remains on the battlefield, the chosen permanents become Treasure artifacts with "{T}, Sacrifice this artifact: Add one mana of any color" and lose all other abilities.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Deadeye Tracker

{1}{B}, {T}: Exile two target cards from an opponent's graveyard. Deadeye Tracker 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.)

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Greedy Freebooter

When Greedy Freebooter dies, scry 1 and create a Treasure token. (To scry 1, look at the top card of your library. You may put that card on the bottom. A Treasure token is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

Tetsuko Umezawa, Fugitive

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

Cloud Pirates

Flying
Cloud Pirates can block only creatures with flying.

Spyglass Siren

Flying
When Spyglass Siren 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.")

Mothdust Changeling

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

Kitesail Freebooter

Flying
When Kitesail Freebooter enters, target opponent reveals their hand. You choose a noncreature, nonland card from it. Exile that card until Kitesail Freebooter leaves the battlefield.

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.)

Storm Fleet Negotiator

Flying
Parley — Whenever Storm Fleet Negotiator attacks, each player reveals the top card of their library. For each nonland card revealed this way, you create a Map token. Then each player draws a card. (A Map token is an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Francisco, Fowl Marauder

Flying
Francisco, Fowl Marauder can't block.
Whenever one or more Pirates you control deal damage to a player, Francisco explores.
Partner (You can have two commanders if both have partner.)

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Amphibian Downpour

Flash
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.