Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent or discards a card.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Mana Web

Whenever a land an opponent controls is tapped for mana, tap all lands that player controls that could produce any type of mana that land could produce.

Gyrus, Waker of Corpses

Gyrus, Waker of Corpses enters the battlefield with a number of +1/+1 counters on it equal to the amount of mana spent to cast it.
Whenever Gyrus attacks, you may exile target creature card with lesser power from your graveyard. If you do, create a token that's a copy of that card and that's tapped and attacking. Exile the token at end of combat.

Belbe, Corrupted Observer

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

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath, Locus of Mana gets +1/+1 for each unspent green mana you have.

Molten Hydra

{1}{R}{R}: Put a +1/+1 counter on Molten Hydra.
{T}, Remove all +1/+1 counters from Molten Hydra: It deals damage to any target equal to the number of +1/+1 counters removed this way.

Have

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Ribbons

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Each opponent loses X life.

Cut // Ribbons

Malakir Mire

Malakir Mire enters the battlefield tapped.
{T}: Add {B}.

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Dig Up

Cleave {1}{B}{B}{G} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Search your library for a [basic land] card, [reveal it,] put it into your hand, then shuffle.

Seeker of Skybreak

Magus of the Vineyard

At the beginning of each player's precombat main phase, that player adds {G}{G}.

Dosan the Falling Leaf

Players can cast spells only during their own turns.

Apocalypse Hydra

Apocalypse Hydra enters the battlefield with X +1/+1 counters on it. If X is 5 or more, it enters the battlefield with an additional X +1/+1 counters on it.
{1}{R}, Remove a +1/+1 counter from Apocalypse Hydra: It deals 1 damage to any target.

Stoneshaker Shaman

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

Heartbeat of Spring

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

Horizon Stone

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

Conqueror's Flail

Equipped creature gets +1/+1 for each color among permanents you control.
As long as Conqueror's Flail is attached to a creature, your opponents can't cast spells during your turn.
Equip {2}

Capricopian

Capricopian enters the battlefield with X +1/+1 counters on it.
{2}: Put a +1/+1 counter on Capricopian, then you may reselect which player Capricopian is attacking. Only the player Capricopian is attacking may activate this ability and only during the declare attackers step. (It can't attack its controller.)

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When Leyline Tyrant dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

Helix Pinnacle

Shroud (This enchantment can't be the target of spells or abilities.)
{X}: Put X tower counters on Helix Pinnacle.
At the beginning of your upkeep, if there are 100 or more tower counters on Helix Pinnacle, you win the game.

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.

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}.

Lavalanche

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

Eladamri's Vineyard

Reap the Past

Return X cards at random from your graveyard to your hand. Exile Reap the Past.

Leyline of Abundance

If Leyline of Abundance 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.

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.

Zhur-Taa Ancient

Umbral Mantle

Equipped creature has "{3}, {Q}: This creature gets +2/+2 until end of turn." ({Q} is the untap symbol.)
Equip {0}

Overabundance

Whenever a player taps a land for mana, that player adds one mana of any type that land produced, and Overabundance deals 1 damage to the player.

Power Surge

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

Zhur-Taa Druid

{T}: Add {G}.
Whenever you tap Zhur-Taa Druid for mana, it deals 1 damage to each opponent.

Rolling Thunder

Rolling Thunder deals X damage divided as you choose among any number of targets.

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

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.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Blinkmoth Urn

At the beginning of each player's precombat main phase, if Blinkmoth Urn is untapped, that player adds {C} for each artifact they control.

Dictate of Karametra

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