msem-instigator

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

Equipped creature gets +1/+1 and has vigilance.
Equip {1}

Counter target spell.
Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of combat on your turn, target creature you control has base power and toughness 4/4 until end of turn.

Haste
Coldhearted Explorer can't block.

Destroy target artifact or enchantment with mana value 4 or less.

Flash
When Collapsed Mine enters, exile another target nonland permanent until Collapsed Mine leaves the battlefield.

When Collapsing Frame enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{2}, Sacrifice Collapsing Frame: Draw a card.

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

Collapsing Ramparts deals damage to target creature equal to twice the number of Satrapies you control.

Whenever a land enters, 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.

Haste
When Collapsing Star Viper enters, you may tap target permanent with mana value X or less.
At the beginning of your upkeep, return Collapsing Star Viper to its owner's hand.

First strike

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 “r3—You may cast a copy of this card from exile without paying its mana cost.”)

(Add a quest counter as this enters. Sacrifice after 6.)
Whenever you cast a permanent spell, add a quest counter.
Choose a color that hasn't been chosen. Search your library for a permanent card that's exactly that color, reveal it, and put it into your hand. Then shuffle.
Exile Collect the World Stones. For the rest of the game, you may spend mana as though it were mana of any color.
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Choose one —
• Create two 1/1 white Soldier creature tokens.
• If you spent three or more mana to cast this spell, create five 1/1 white Soldier creature tokens.

Once each turn, when you foretell a card or cast a foretold spell, you may create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

{T}: Add one mana of any color.
Augmented — Whenever a nontoken creature you control enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on it.

Whenever a token creature you control dies, each opponent loses 2 life.

Whenever you draw a card, you may exile the top card of your library.
{3}{U}{U}, Sacrifice Collector of Memories: Shuffle your hand into your library, then put each card exiled with Collector of Memories into its owner's hand.

Creatures you control named Colocolo can't be blocked and have ward {2}.
{U}{U}: Put an inspiration counter on target creature. It's named Colocolo in addition to its other names for as long as it has an inspiration counter on it.

Reach
When Colonial Effigy dies, create a 1/1 white Spirit creature token with flying.

When Colony Queen enters, create three 1/1 green Insect creature tokens.
Insect tokens you control have flying and deathtouch.