msem-instigator

When Climbing the Oldest Mountain enters the battlefield, draw a card, then choose a card name.
Whenever a creature you control with the chosen name deals combat damage to a player, put two +1/+1 counters on it.

Equipped creature has hexproof. (That creature can't be the target of spells or abilities your opponents control.)
Equip {0}

Clockwork Gaucho enters the battlefield with a +1/+1 counter on it.
Other artifact creatures you control get +1/+1 for each +1/+1 counter on Clockwork Gaucho.
{T}: Put a +1/+1 counter on Clockwork Gaucho.

Enchant artifact
Enchanted artifact is a creature with base power and toughness 3/3 in addition to its other types.
Enchanted artifact has prowess and “Once each turn, when you cast a noncreature spell, you may untap this artifact.”

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

Flying
{U}: Put Cloud Sovereign on top of its owner's library.
Foresee — As you draw Cloud Sovereign, you may reveal it and pay {1}{W}. When you do, create a 1/1 white Bird creature token with flying.

Flying
Whenever you cast a spell, create a 1/1 blue Boar Dragon creature token with flying.

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

Flying
Whenever Cloudfisher deals combat damage to a creature, gain control of that creature for as long as you control Cloudfisher.
Whenever Cloudfisher deals combat damage to a player, gain control of target land that player controls for as long as you control Cloudfisher.

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

When Cloven Forms enters the battlefield, reveal the top three cards of your library. Put all creature cards revealed this way into your hand and the rest into your graveyard.
{5}{G}{G}{G}, Exile Cloven Forms: Put a creature card from or hand or command zone onto the battlefield. Create a token that's a copy of it, except the token isn't legendary.

{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 one mana of any color.
{T}: Put a charge counter on Coalition Relic.
At the beginning of your precombat main phase, remove all charge counters from Coalition Relic. Add one mana of any color for each charge counter removed this way.

({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}.

Submerge each creature you control. At the beginning of the next end step, you may turn any number of face down creatures you control face up. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Trample, haste
Crew—Tap three untapped artifacts and/or creatures you control.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other artifacts you control have extort.
Whenever a spell you control resolves, if it was extorted three or more times, each opponent discards a card and you draw a card.

Dominance — At the beginning of combat on your turn, if you control the creature with the greatest power or tied for the greatest power, you may pay {R}. If you do, gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.

When Cognitive Fumigator enters the battlefield, target opponent reveals their hand. You may choose a nonland card from it and exile that card. If you do, that player draws a card.
Recite {2}{U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters the battlefield or if it would leave the battlefield.)

Creatures have “Whenever this creature attacks or blocks, it fights another target creature.”

Whenever a land enters the battlefield, Collapsing Realities deals 2 damage to each player.

{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.

Pressure {B}{G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Search your library and/or graveyard for a creature card with mana value 3 or less and put it onto the battlefield. If you searched your library this way, shuffle.

Create a 1/1 colorless Construct Actor creature token for each creature you control.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “III—You may cast a copy of this card from exile without paying its mana cost.”)