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

Other Merfolk you control get +1/+1.

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

Equipped creature has "You may look at the top card of your library any time" and "Whenever this creature attacks, 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 that creature, then put the card back or put it into your graveyard.) Equip {2}

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Counter target spell unless its controller pays {2}.

{1}{G}{U}: Put a +1/+1 counter on target creature you control. Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy. At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.

When Cenote Scout enters the battlefield, 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.)

At the beginning of combat on your turn, Deepfathom Echo explores. Then you may have it become a copy of another creature you control until end of turn. (To have this creature explore, 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.)

Whenever a creature you control explores, Merfolk Cave-Diver gets +1/+0 until end of turn and can't be blocked this turn.

Whenever a creature you control explores a land card, you may put a land card from your hand onto the battlefield tapped. Whenever a creature you control explores a nonland card, put a +1/+1 counter on Nicanzil, Current Conductor.

Vigilance When River Herald Guide enters the battlefield, 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.)

When River Herald Scout enters the battlefield, 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.)

Ward {2} As Roaming Throne enters the battlefield, 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.

{2}{G}: Seeker of Sunlight explores. Activate only as a sorcery. (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.)

Vigilance Whenever Sentinel of the Nameless City enters the battlefield or attacks, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

When Topography Tracker enters the battlefield, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.") If a creature you control would explore, instead it explores, then it explores again.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

You may look at the top card of your library any time. You may cast Merfolk spells from the top of your library. Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

Draw two cards, then discard two cards. Untap up to three lands.

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

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

Draw three cards. Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Each other Wizard creature you control enters the battlefield with an additional +1/+1 counter on it. {2}, Remove a +1/+1 counter from a creature you control: Draw a card.

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

Whenever a creature enters the battlefield under your control, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.) Whenever you cast a spell that targets a creature you control, draw a card.

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}.)

Tishana, Voice of Thunder's power and toughness are each equal to the number of cards in your hand. You have no maximum hand size. When Tishana enters the battlefield, draw a card for each creature you control.

Whenever you draw your second card each turn, you may put a land card from your hand onto the battlefield tapped.

When Spelunking enters the battlefield, 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 the battlefield untapped.

Return target creature to its owner's hand. If it was tapped, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.) This spell costs {1} less to cast if it's bargained. Counter target spell.

({T}: Add {G} or {U}.) As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

As Cavern of Souls enters the battlefield, 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, and that spell can't be countered.

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

({T}: Add {G}.)

({T}: Add {G}.)

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island. {T}: Add {G} or {U}.

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

{T}: Add {C}. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Kitchen enters the battlefield tapped. {T}: Add {G} or {U}. {4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Llanowar Reborn enters the battlefield tapped. {T}: Add {G}. Graft 1 (This land enters the battlefield with a +1/+1 counter on it. Whenever a creature enters the battlefield, you may move a +1/+1 counter from this land onto it.)

Hideaway 4 (When this land enters the battlefield, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.) Mosswort Bridge enters the battlefield tapped. {T}: Add {G}. {G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Path of Ancestry enters the battlefield 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.)

Pit of Offerings enters the battlefield tapped. When Pit of Offerings enters the battlefield, exile up to three target cards from graveyards. {T}: Add {C}. {T}: Add one mana of any of the exiled cards' colors.

Public Thoroughfare enters the battlefield tapped. When Public Thoroughfare enters the battlefield, sacrifice it unless you tap an untapped artifact or land you control. {T}: Add one mana of any color.

{T}: Add {C}. {4}, {T}: Target creature can't be blocked this turn.

As Secluded Courtyard enters the battlefield, 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.

Simic Growth Chamber enters the battlefield tapped. When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand. {T}: Add {G}{U}.

Simic Guildgate enters the battlefield tapped. {T}: Add {G} or {U}.

Temple of Mystery enters the battlefield tapped. When Temple of Mystery enters the battlefield, scry 1. {T}: Add {G} or {U}.

{T}: Add {C}{C}. Activate only if you control five or more lands.

Thriving Isle enters the battlefield tapped. As Thriving Isle enters the battlefield, choose a color other than blue. {T}: Add {U} or one mana of the chosen color.

As Unclaimed Territory enters the battlefield, 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.

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

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

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

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

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

{1}, {T}: Add {G}{U}.

{T}: Add {C}{C}.

Return all attacking creatures to their owner's hand.

Counter target spell.

As an additional cost to cast this spell, you may collect evidence 8. (Exile cards with total mana value 8 or greater from your graveyard.) Search your library for a basic land card. If evidence was collected, instead search your library for a creature or land card. Reveal that card, put it into your hand, then shuffle.

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.) If this spell was bargained, target land you control becomes a 3/3 Elemental creature with haste that's still a land. Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Choose one — • Destroy target artifact or enchantment. • Target creature you control explores, then it explores again. (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 that creature, then put the card back or put it into your graveyard. Then repeat this process.)

{2}, Sacrifice this artifact: Draw a card.

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

{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery. (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 that creature, then put the card back or put it into your graveyard.)

Hexproof (This creature can't be the target of spells or abilities your opponents control.)