Vault of Champions

Vault of Champions enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Despark

Exile target permanent with mana value 4 or greater.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Scrubland

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Dimir Signet

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Misleading Signpost

Flash
When Misleading Signpost enters during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or their permanents.)
{T}: Add {U}.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on Midnight Clock.
At the beginning of each upkeep, put an hour counter on Midnight Clock.
When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Crowded Crypt

{T}: Add {B}.
Whenever a creature you control dies, put a corpse counter on Crowded Crypt.
{4}{B}{B}, {T}, Sacrifice Crowded Crypt: Create a 2/2 black Zombie creature token with decayed for each corpse counter on Crowded Crypt. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Azorius Signet

Tundra

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Arcane Signet

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

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Sol Ring

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Command Tower

Exotic Orchard

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

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Forger's Foundry

{T}: Add {U}. When you spend this mana to cast an instant or sorcery spell with mana value 3 or less, you may exile that spell instead of putting it into its owner's graveyard as it resolves.
{3}{U}{U}, {T}: You may cast any number of spells from among cards exiled with Forger's Foundry without paying their mana costs. Activate only as a sorcery.

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Orzhov Signet

Tainted Field

{T}: Add {C}.
{T}: Add {W} or {B}. Activate only if you control a Swamp.

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Arcane Sanctum

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

Underground Sea

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.