Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Mana Short

Tap all lands target player controls and that player loses all unspent mana.

Stonework Packbeast

Stonework Packbeast is also a Cleric, Rogue, Warrior, and Wizard.
{2}: Add one mana of any color.

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Prismite

Pygmy Hippo

Whenever this creature attacks and isn't blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, this creature assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of {C} equal to the amount of mana that player lost this way.

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.

Drain Power

Target player activates a mana ability of each land they control. Then that player loses all unspent mana and you add the mana lost this way.

Zendikar Resurgent

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)
Whenever you cast a creature spell, draw a card.

Heartbeat of Spring

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

Crossroads Candleguide

When this creature enters, exile up to one target card from a graveyard.
{2}: Add one mana of any color.

Mycosynth Lattice

All permanents are artifacts in addition to their other types.
All cards that aren't on the battlefield, spells, and permanents are colorless.
Players may spend mana as though it were mana of any color.

Cascading Cataracts

Indestructible
{T}: Add {C}.
{5}, {T}: Add five mana in any combination of colors.

Kodama's Reach

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.

Walking Ballista

This creature enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on this creature.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Garenbrig Growth

Return target creature or land card from your graveyard to your hand. (Then exile this card. You may cast the enchantment later from exile.)

Virtue of Strength

If you tap a basic land for mana, it produces three times as much of that mana instead.

Virtue of Strength // Garenbrig Growth

Extraplanar Lens

Imprint — When this artifact enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Vernal Bloom

Whenever a Forest is tapped for mana, its controller adds an additional {G}.

Endless One

This creature enters with X +1/+1 counters on it.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Vorinclex, Voice of Hunger

Trample
Whenever you tap a land for mana, add one mana of any type that land produced.
Whenever an opponent taps a land for mana, that land doesn't untap during its controller's next untap step.

Energy Refractor

When this artifact enters, draw a card.
{2}: Add one mana of any color.

Cultivate

Caged Sun

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Nissa, Who Shakes the World

Whenever you tap a Forest for mana, add an additional {G}.
+1: Put three +1/+1 counters on up to one target noncreature land you control. Untap it. It becomes a 0/0 Elemental creature with vigilance and haste that's still a land.
−8: You get an emblem with "Lands you control have indestructible." Search your library for any number of Forest cards, put them onto the battlefield tapped, then shuffle.

Shifting Wall

Defender (This creature can't attack.)
This creature enters with X +1/+1 counters on it.

Dictate of Karametra

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

Stonecoil Serpent

Reach, trample, protection from multicolored
This creature enters with X +1/+1 counters on it.

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.

Regal Behemoth

Trample
When this creature enters, you become the monarch.
Whenever you tap a land for mana while you're the monarch, add an additional one mana of any color.

Kruphix, God of Horizons

Indestructible
As long as your devotion to green and blue is less than seven, Kruphix isn't a creature.
You have no maximum hand size.
If you would lose unspent mana, that mana becomes colorless instead.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Urn of Godfire

{2}: Add one mana of any color.
{6}, {T}, Sacrifice this artifact: Destroy target creature or enchantment.

Wilderness Reclamation

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

Signpost Scarecrow

Vigilance
{2}: Add one mana of any color.

Nyxbloom Ancient

Trample
If you tap a permanent for mana, it produces three times as much of that mana instead.