Yew Spirit

{2}{G}{G}: Yew Spirit gets +X/+X until end of turn, where X is its power.

Sol Ring

Serpent of the Endless Sea

Serpent of the Endless Sea's power and toughness are each equal to the number of Islands you control.
Serpent of the Endless Sea can't attack unless defending player controls an Island.

Pestilent Spirit

Menace, deathtouch
Instant and sorcery spells you control have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Zephyr Spirit

When Zephyr Spirit blocks, return it to its owner's hand.

Mist-Syndicate Naga

Ninjutsu {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Mist-Syndicate Naga deals combat damage to a player, create a token that's a copy of Mist-Syndicate Naga.

Simic Signet

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Harrier Naga

Zephyr Boots

Equipped creature has flying.
Whenever equipped creature deals combat damage to a player, draw a card, then discard a card.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Diviner Spirit

Whenever Diviner Spirit deals combat damage to a player, you and that player each draw that many cards.

Spirit

Stormrider Spirit

Naga Oracle

When Naga Oracle enters, surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Naga Vitalist

{T}: Add one mana of any type that a land you control could produce.

Koma's Coil

Swamp

Molting Snakeskin

Enchant creature
Enchanted creature gets +2/+0 and has "{2}{B}: Regenerate this creature."

Kadena, Slinking Sorcerer

The first face-down creature spell you cast each turn costs {3} less to cast.
Whenever a face-down creature you control enters, draw a card.

Troublesome Spirit

Flying
At the beginning of your end step, tap all lands you control.

Steelclad Spirit

Defender
Whenever an enchantment you control enters, Steelclad Spirit can attack this turn as though it didn't have defender.

Sultai Charm

Choose one —
• Destroy target monocolored creature.
• Destroy target artifact or enchantment.
• Draw two cards, then discard a card.

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.)

Soulsworn Spirit

Soulsworn Spirit can't be blocked.
When Soulsworn Spirit enters, detain target creature an opponent controls. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)

Serpent Assassin

When Serpent Assassin enters, you may destroy target nonblack creature.

Hooded Hydra

Hooded Hydra enters with X +1/+1 counters on it.
When Hooded Hydra dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As Hooded Hydra is turned face up, put five +1/+1 counters on it.

Spirit Away

Enchant creature
You control enchanted creature.
Enchanted creature gets +2/+2 and has flying.

Chameleon Spirit

As Chameleon Spirit enters, choose a color.
Chameleon Spirit's power and toughness are each equal to the number of permanents of the chosen color your opponents control.

Wind Spirit

Flying
Menace (This creature can't be blocked except by two or more creatures.)

Spire Serpent

Defender
Metalcraft — As long as you control three or more artifacts, Spire Serpent gets +2/+2 and can attack as though it didn't have defender.

Scrapdiver Serpent

Scrapdiver Serpent can't be blocked as long as defending player controls an artifact.

Serpent's Gift

Target creature gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Serpent of Yawning Depths

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.

Forest

Sidewinder Naga

As long as you control a Desert or there is a Desert card in your graveyard, Sidewinder Naga gets +1/+0 and has trample.

Steelclad Serpent

Steelclad Serpent can't attack unless you control another artifact.

Snake Pit

Whenever an opponent casts a blue or black spell, you may create a 1/1 green Snake creature token.

Island

Feiyi Snake

Reach (This creature can block creatures with flying.)

Serpent Generator

{4}, {T}: Create a 1/1 colorless Snake artifact creature token. It has "Whenever this creature deals damage to a player, that player gets a poison counter." (A player with ten or more poison counters loses the game.)

Arcane Signet

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

Feed the Serpent

Koma, Cosmos Serpent

This spell can't be countered.
At the beginning of each upkeep, create a 3/3 blue Serpent creature token named Koma's Coil.
Sacrifice another Serpent: Choose one —
• Tap target permanent. Its activated abilities can't be activated this turn.
• Koma, Cosmos Serpent gains indestructible until end of turn.

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Snake

Naga Eternal

Slinking Serpent

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)

Desiccated Naga

{3}{B}: Target opponent loses 2 life and you gain 2 life. Activate only if you control a Liliana planeswalker.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Consume Spirit

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Harbor Serpent

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Harbor Serpent can't attack unless there are five or more Islands on the battlefield.

Serpentine Curve

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is one plus the total number of instant and sorcery cards you own in exile and in your graveyard.

Accursed Spirit

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Rend Spirit

Pact of the Serpent

Choose a creature type. Target player draws X cards and loses X life, where X is the number of creatures they control of the chosen type.

Stormcloud Spirit

Flying (This creature can't be blocked except by creatures with flying or reach.)

Ascendant Spirit

{S}{S}: Ascendant Spirit becomes a Spirit Warrior with base power and toughness 2/3.
{S}{S}{S}: If Ascendant Spirit is a Warrior, put a flying counter on it and it becomes a Spirit Warrior Angel with base power and toughness 4/4.
{S}{S}{S}{S}: If Ascendant Spirit is an Angel, put two +1/+1 counters on it and it gains "Whenever this creature deals combat damage to a player, draw a card."

Will of the Naga

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Orchard Spirit

Orchard Spirit can't be blocked except by creatures with flying or reach.

Gearseeker Serpent

This spell costs {1} less to cast for each artifact you control.
{5}{U}: Gearseeker Serpent can't be blocked this turn.

Spirit of Malevolence

When Spirit of Malevolence dies, each opponent loses 1 life and you gain 1 life.

Cryptic Serpent

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Cloud Spirit

Flying
Cloud Spirit can block only creatures with flying.

Fractal

Spirit of the Night

Flying, trample, haste, protection from black
Spirit of the Night has first strike as long as it's attacking.

Watchful Naga

You may exert Watchful Naga as it attacks. When you do, draw a card. (An exerted creature won't untap during your next untap step.)