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.)

Dingus Egg

Whenever a land is put into a graveyard from the battlefield, Dingus Egg deals 2 damage to that land's controller.

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.

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.

Umbral Mantle

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

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.

Stoneshaker Shaman

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

Heartbeat of Spring

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

Mana Flare

Manabarbs

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

Harsh Mentor

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

Staff of Domination

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

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}.

Magus of the Vineyard

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

Zhur-Taa Druid

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

Vazi, Keen Negotiator

Haste
{T}: Target opponent creates X Treasure tokens, where X is the number of Treasure tokens you created this turn.
Whenever an opponent casts a spell or activates an ability, if mana from a Treasure was spent to cast it or activate it, put a +1/+1 counter on target creature, then draw a card.

Rites of Flourishing

At the beginning of each player's draw step, that player draws an additional card.
Each player may play an additional land on each of their turns.

The Gitrog Monster

Deathtouch
At the beginning of your upkeep, sacrifice The Gitrog Monster unless you sacrifice a land.
You may play an additional land on each of your turns.
Whenever one or more land cards are put into your graveyard from anywhere, draw a card.

Dictate of Karametra

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

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}.

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.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

Soul of Windgrace

Whenever Soul of Windgrace enters or attacks, you may put a land card from a graveyard onto the battlefield tapped under your control.
{G}, Discard a land card: You gain 3 life.
{1}{R}, Discard a land card: Draw a card.
{2}{B}, Discard a land card: Soul of Windgrace gains indestructible until end of turn. Tap it.