msem-instigator

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell or activate an ability of a legendary permanent.

{T}: Add {C}.
{1}, {T}, Sacrifice Chikyu League Arena: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Chiseled Cliffside enters the battlefield tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

As Choked Estuary enters the battlefield, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters the battlefield tapped.
{T}: Add {U} or {B}.

During your opponents' turns, Chroma, the Faerie Circle has all basic land types in all zones.
Chroma, the Faerie Circle enters the battlefield tapped.

Equipped creature has haste.
Sacrifice Cinderblade: Equipped creature gains +2/+2 until end of turn.
Equip {1}

As Citadel Gates enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {B}, {R}, or {G}.

{T}: Add {C}.
{1}{C}{C}, {T}: Return target legendary creature to its owner's hand.

{T}: Add {C}.
{3}, {T}, Sacrifice City Gate: Put two +1/+1 counters on target creature you control that attacked this turn.

{T}, Pay 1 life: Add {W} or {U}.
{1}, {T}, Sacrifice Cleared Vault: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Cliffside Entrance enters the battlefield tapped unless you have 15 or less life.
{T}: Add {R} or {W}.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
Tap four untapped creatures you control: Unlock Clockwork Astrolarium. If the revealed card is white, put it into your hand. Otherwise, put it on top of your library.

{T}: Add {C}.
{T}, Pay 1 life: Add {W} or {B}.

({T}: Add {U}.)
Cloudbank enters the battlefield tapped.
When Cloudbank enters the battlefield, target creature gains flying until end of turn.

Cloudcover Heights enters the battlefield tapped unless you control a Forest.
{T}: Add {R} or {W}.

({T}: Add {R}.)
As Cloudpeak Spires enters the battlefield, you may pay 1 life. If you don't, Cloudpeak Spires enters the battlefield tapped.
Basic lands you control have “{T}: Add {R}.”

({T}: Add {R} or {W}.)
Cloudsteel Summit enters the battlefield tapped.
{1}, {T}: Add {R}{R} or {W}{W}.

{T}: Add {C}.
{1}: Clutch of the Coil becomes a 1/1 Snake creature with poisonous 2 until end of turn. It's still a land. (Whenever this creature deals combat damage to a player, that player gets two poison counters.)

({T}: Add {W}, {U}, or {B}.)
Coastal Dominion enters the battlefield tapped.

Coastal Metropolis enters the battlefield tapped unless you have 15 or less life.
{T}: Add {W} or {U}.

{T}: Add {C}.
{1}, {T}, Return Collapsing Ground to its owner's hand: Add one mana of any color.

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{5}{B}, {T}, Sacrifice Collapsing Ridges: Return target creature card from a graveyard to the battlefield under your control. Activate only as a sorcery.

Combined Generator can't be blocked except by three or more creatures.

Enchant creature
Enchanted creature must be blocked if able.

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