Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, this creature deals 2 damage to that player.

Sol Ring

Ruric Thar, the Unbowed

Vigilance, reach
Ruric Thar attacks each combat if able.
Whenever a player casts a noncreature spell, Ruric Thar deals 6 damage to that player.

Xantcha, Sleeper Agent

Xantcha enters under the control of an opponent of your choice.
Xantcha attacks each combat if able and can't attack its owner or planeswalkers its owner controls.
{3}: Xantcha's controller loses 2 life and you draw a card. Any player may activate this ability.

Arcane Signet

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

Green Sun's Twilight

Reveal the top X plus one cards of your library. Choose a creature card and/or a land card from among them. Put those cards into your hand and the rest on the bottom of your library in a random order. If X is 5 or more, instead put the chosen cards onto the battlefield or into your hand and the rest on the bottom of your library in a random order.

Forest

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Mountain

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Spiteful Visions

At the beginning of each player's draw step, that player draws an additional card.
Whenever a player draws a card, this enchantment deals 1 damage to that player.

Farseek

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

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Golgari Signet

Swamp

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Veteran Explorer

When this creature dies, each player may search their library for up to two basic land cards, put them onto the battlefield, then shuffle.

Cultivate

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.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Keeper of Progenitus

Whenever a player taps a Mountain, Forest, or Plains for mana, that player adds one mana of any type that land produced.

Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, this creature deals 1 damage to that player.
{3}{R}{R}: This creature gets +3/+3 and gains menace until end of turn.

Belbe, Corrupted Observer

At the beginning of each postcombat main phase, the active player adds {C}{C} for each of your opponents who lost life this turn. (Damage causes loss of life.)

Seeker of Skybreak

Staff of Domination

{1}: Untap this artifact.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Magebane Lizard

Whenever a player casts a noncreature spell, this creature deals damage to that player equal to the number of noncreature spells they've cast this turn.

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Twisted Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{R}{G} ({B}{R}{G}, Discard this card: Draw a card.)

Hell to Pay

Hell to Pay deals X damage to target creature. Create a number of tapped Treasure tokens equal to the amount of excess damage dealt to that creature this way.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Sword of the Paruns

As long as equipped creature is tapped, tapped creatures you control get +2/+0.
As long as equipped creature is untapped, untapped creatures you control get +0/+2.
{3}: You may tap or untap equipped creature.
Equip {3}

Zhur-Taa Ancient

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Zhur-Taa Druid

{T}: Add {G}.
Whenever you tap this creature for mana, it deals 1 damage to each opponent.

Sign in Blood

Target player draws two cards and loses 2 life.

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Yurlok of Scorch Thrash

Vigilance
A player losing unspent mana causes that player to lose that much life.
{1}, {T}: Each player adds {B}{R}{G}.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Stoneshaker Shaman

At the beginning of each player's end step, that player sacrifices an untapped land of their choice.

Llanowar Elves

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek deals damage equal to that spell's mana value to any target.

Lavalanche

Lavalanche deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Riveteers Overlook

When this land enters, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Nightshade Harvester

Whenever a land an opponent controls enters, that player loses 1 life. Put a +1/+1 counter on this creature.

Gruul Signet

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Tyvar, Jubilant Brawler

You may activate abilities of creatures you control as though those creatures had haste.
+1: Untap up to one target creature.
−2: Mill three cards, then you may return a creature card with mana value 2 or less from your graveyard to the battlefield.

Bedevil

Destroy target artifact, creature, or planeswalker.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Command Tower

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Cindervines

Whenever an opponent casts a noncreature spell, this enchantment deals 1 damage to that player.
{1}, Sacrifice this enchantment: Destroy target artifact or enchantment. This enchantment deals 2 damage to that permanent's controller.

Terminate

Destroy target creature. It can't be regenerated.

Dictate of Karametra

Flash
Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Harmonize

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

Rootweaver Druid

When this creature enters, each opponent may search their library for up to three basic land cards. They each put one of those cards onto the battlefield tapped under your control and the rest onto the battlefield tapped under their control. Then each player who searched their library this way shuffles.

Magus of the Candelabra

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Putrefy

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

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Power Surge

At the beginning of each player's upkeep, this enchantment deals X damage to that player, where X is the number of untapped lands they controlled at the beginning of this turn.

Rakdos Signet

Exocrine

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Bio-plasmic Barrage — When this creature enters, it deals X damage to each player and each other creature.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Sakura-Tribe Elder

Sacrifice this creature: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Leyline of Abundance

If this card is in your opening hand, you may begin the game with it on the battlefield.
Whenever you tap a creature for mana, add an additional {G}.
{6}{G}{G}: Put a +1/+1 counter on each creature you control.

Victory Chimes

Untap this artifact during each other player's untap step.
{T}: A player of your choice adds {C}.

Scytheclaw Raptor

Whenever a player casts a spell, if it's not their turn, this creature deals 4 damage to them.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.