Head Games

Target opponent puts the cards from their hand on top of their library. Search that player's library for that many cards. The player puts those cards into their hand, then shuffles.

Vivid Marsh

Vivid Marsh enters tapped with two charge counters on it.
{T}: Add {B}.
{T}, Remove a charge counter from Vivid Marsh: Add one mana of any color.

Azorius Signet

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.

Vivid Meadow

Vivid Meadow enters tapped with two charge counters on it.
{T}: Add {W}.
{T}, Remove a charge counter from Vivid Meadow: Add one mana of any color.

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

Coldsteel Heart

Coldsteel Heart enters tapped.
As Coldsteel Heart enters, choose a color.
{T}: Add one mana of the chosen color.

Mystic Monastery

Mystic Monastery enters tapped.
{T}: Add {U}, {R}, or {W}.

Command Tower

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

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Plains

Jungle Shrine

Jungle Shrine enters tapped.
{T}: Add {R}, {G}, or {W}.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this artifact: Add one mana of any color.")

Forest

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Savage Lands

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

Vivid Crag

Vivid Crag enters tapped with two charge counters on it.
{T}: Add {R}.
{T}, Remove a charge counter from Vivid Crag: Add one mana of any color.

Rampant Growth

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

Swamp

Farseek

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

Flamekin Village

As Flamekin Village enters, you may reveal an Elemental card from your hand. If you don't, Flamekin Village enters tapped.
{T}: Add {R}.
{R}, {T}: Target creature gains haste until end of turn.

Cultivate

Vault of Whispers

Arcane Sanctum

Arcane Sanctum enters tapped.
{T}: Add {W}, {U}, or {B}.

Island

Spectral Searchlight

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

Survivors' Encampment

{T}: Add {C}.
{T}, Tap an untapped creature you control: Add one mana of any color.

Fellwar Stone

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

Sol Ring

O-Kagachi, Vengeful Kami

Flying, trample
Whenever O-Kagachi, Vengeful Kami deals combat damage to a player, if that player attacked you during their last turn, exile target nonland permanent that player controls.

Cascading Cataracts

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

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Mountain

Commander's Sphere

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

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Izzet Signet

Boros Signet

Seat of the Synod

Gilded Lotus

Painful Truths

Converge — You draw X cards and you lose X life, where X is the number of colors of mana spent to cast this spell.

Tempt with Discovery

Tempting offer — Search your library for a land card and put it onto the battlefield. Each opponent may search their library for a land card and put it onto the battlefield. For each opponent who searches a library this way, search your library for a land card and put it onto the battlefield. Then each player who searched a library this way shuffles.

Gruul Signet

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Vivid Grove

Vivid Grove enters tapped with two charge counters on it.
{T}: Add {G}.
{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.