Caves of Koilos

{T}: Add {C}.
{T}: Add {W} or {B}. Caves of Koilos deals 1 damage to you.

Swamp

Obstinate Gargoyle

Obstinate Gargoyle has flying as long as it's modified. (Equipment, Auras you control, and counters are modifications.)
Persist (When this creature 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.)

Plains

Celestial Ancient

Flying
Whenever you cast an enchantment spell, put a +1/+1 counter on each creature you control.

Thought Vessel

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

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Isolated Chapel

Isolated Chapel enters the battlefield tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Arna Kennerüd, Skycaptain

Flying, lifelink
Ward—Discard a card.
Whenever a modified creature you control attacks, double the number of each kind of counter on it. Then for each nontoken permanent attached to it, create a token that's a copy of that permanent attached to that creature.

Starfield Mystic

Enchantment spells you cast cost {1} less to cast.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on Starfield Mystic.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Shipwreck Marsh

Shipwreck Marsh enters the battlefield tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Morphic Pool

Morphic Pool enters the battlefield tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Vault of Champions

Vault of Champions enters the battlefield tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Envoy of the Ancestors

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Modified creatures you control have lifelink. (Equipment, Auras you control, and counters are modifications.)

Unforgiving One

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Unforgiving One attacks, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the number of modified creatures you control. (Equipment, Auras you control, and counters are modifications.)

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Chromatic Lantern

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

Pearl-Ear, Imperial Advisor

Lifelink
Enchantment spells you cast have affinity for Auras. (They cost {1} less to cast for each Aura you control.)
Whenever you cast an Aura spell that targets a modified permanent you control, draw a card. (Equipment, Auras you control, and counters are modifications.)

Throw a Line

Distribute two +1/+1 counters among one or two target creatures. (Then exile this card. You may cast the creature later from exile.)

Ondu Knotmaster

Lifelink
Whenever another modified creature you control dies, put two +1/+1 counters on Ondu Knotmaster.

Ondu Knotmaster // Throw a Line

Watery Grave

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

Okiba Salvage

Return target creature or Vehicle card from your graveyard to the battlefield. Then put two +1/+1 counters on that permanent if you control an artifact and an enchantment.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Savior of the Sleeping

Vigilance
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on Savior of the Sleeping.

Guardian of the Forgotten

Vigilance
Whenever a modified creature you control dies, manifest the top card of your library. (Equipment, Auras you control, and counters are modifications. To manifest a card, put the top card of your library onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Commander's Sphere

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

Lethal Throwdown

As an additional cost to cast this spell, sacrifice a creature or sacrifice a modified creature. (Equipment, Auras you control, and counters are modifications.)
Destroy target creature or planeswalker. If the modified creature was sacrificed, draw a card.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Shattered Sanctum

Shattered Sanctum enters the battlefield tapped unless you control two or more other lands.
{T}: Add {W} or {B}.

Command Tower

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

Sol Ring

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Lethal Exploit

Target creature gets -2/-2 until end of turn. It gets an additional -1/-1 until end of turn for each modified creature you controlled as you cast this spell. (Equipment, Auras you control, and counters are modifications.)

Drowned Catacomb

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Talisman of Hierarchy

{T}: Add {C}.
{T}: Add {W} or {B}. Talisman of Hierarchy deals 1 damage to you.

Towashi Guide-Bot

When Towashi Guide-Bot enters the battlefield, put a +1/+1 counter on target creature you control.
{4}, {T}: Draw a card. This ability costs {1} less to activate for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

Island

Neva, Stalked by Nightmares

Menace
When Neva, Stalked by Nightmares enters the battlefield, return target creature or enchantment card from your graveyard to your hand.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on Neva, then scry 1.

Hero of Iroas

Aura spells you cast cost {1} less to cast.
Heroic — Whenever you cast a spell that targets Hero of Iroas, put a +1/+1 counter on Hero of Iroas.