Knowledge Seeker

Vigilance
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.
When this creature dies, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Swamp

Sold Out

Exile target creature. If it was dealt damage this turn, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Abandon Attachments

You may discard a card. If you do, draw two cards.

Deadly Precision

As an additional cost to cast this spell, pay {4} or sacrifice an artifact or creature.
Destroy target creature.

Callous Inspector

Menace (This creature can't be blocked except by two or more creatures.)
When this creature dies, it deals 1 damage to you. Create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Canyon Crawler

Deathtouch
When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Professor Zei, Anthropologist

{T}, Discard a card: Draw a card.
{1}, {T}, Sacrifice Professor Zei: Return target instant or sorcery card from your graveyard to your hand. Activate only during your turn.

Octopus Form

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Giant Koi

Waterbend {3}: This creature can't be blocked this turn. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Day of Black Sun

Each creature with mana value X or less loses all abilities until end of turn. Destroy those creatures.

Otter-Penguin

Whenever you draw your second card each turn, this creature gets +1/+2 until end of turn and can't be blocked this turn.

Barrels of Blasting Jelly

{1}: Add one mana of any color. Activate only once each turn.
{5}, {T}, Sacrifice this artifact: It deals 5 damage to target creature.

Swampsnare Trap

This spell costs {1} less to cast if it targets a creature with flying.
Enchant creature
Enchanted creature gets -5/-3.

Foggy Swamp Spirit Keeper

Lifelink
Whenever you draw your second card each turn, create a 1/1 colorless Spirit creature token with "This token can't block or be blocked by non-Spirit creatures."

Watery Grasp

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Waterbend {5}: Enchanted creature's owner shuffles it into their library. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Geyser Leaper

Flying
Waterbend {4}: Draw a card, then discard a card. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Obsessive Pursuit

When this enchantment enters and at the beginning of your upkeep, you lose 1 life and create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you attack, put X +1/+1 counters on target attacking creature, where X is the number of permanents you've sacrificed this turn. If X is three or greater, that creature gains lifelink until end of turn.

Azula Always Lies

Choose one or both —
• Target creature gets -1/-1 until end of turn.
• Put a +1/+1 counter on target creature.

Island

Fire Nation Warship

Reach
When this Vehicle dies, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Iguana Parrot

Flying, vigilance
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)