Arcane Signet

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

Island

Thousand-Faced Shadow

Ninjutsu {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Flying
When Thousand-Faced Shadow enters from your hand, if it's attacking, create a token that's a copy of another target attacking creature. The token enters tapped and attacking.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Yuriko, the Tiger's Shadow

Commander ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Ulamog's Dreadsire

Vigilance
Ward—Sacrifice a permanent with mana value 1 or greater.
{T}: Create a 10/10 colorless Eldrazi creature token.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Emmara, Soul of the Accord

Whenever Emmara, Soul of the Accord becomes tapped, create a 1/1 white Soldier creature token with lifelink.

Forest

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Silver-Fur Master

Ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Ninjutsu abilities you activate cost {1} less to activate.
Other Ninja and Rogue creatures you control get +1/+1.

Satoru, the Infiltrator

Menace
Whenever Satoru, the Infiltrator and/or one or more other nontoken creatures you control enter, if none of them were cast or no mana was spent to cast them, draw a card.

Mountain

Chrome Mox

Imprint — When Chrome Mox enters, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.

Plains

Dark Ritual

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Strix Serenade

Counter target artifact, creature, or planeswalker spell. Its controller creates a 2/2 blue Bird creature token with flying.

Snapcaster Mage

Flash
When Snapcaster Mage enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Bello, Bard of the Brambles

During your turn, each non-Equipment artifact and non-Aura enchantment you control with mana value 4 or greater is a 4/4 Elemental creature in addition to its other types and has indestructible, haste, and "Whenever this creature deals combat damage to a player, draw a card."

Mox Diamond

If Mox Diamond would enter, you may discard a land card instead. If you do, put Mox Diamond onto the battlefield. If you don't, put it into its owner's graveyard.
{T}: Add one mana of any color.

Fellwar Stone

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

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Command Tower

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Swamp

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)