msem-instigator

Bustling Marketplace can't be sacrificed.
{T}: Add one mana of any type that a land you control could produce.
{0}: Bustling Marketplace's owner may draw a card. If they do, untap Bustling Marketplace and gain control of it until end of turn. Only your opponents may activate this ability and only once each turn during their turn.

Deathtouch
Once each turn, you may cast a creature spell from your graveyard by paying life equal to its mana value rather than paying its mana cost.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets -2/-2.
Whenever enchanted creature blocks, its controller loses 2 life.

Permanents you control with mana value 1 or less have first strike, haste, and lifelink.

Creatures you control get +0/+1 and can attack as though they didn't have defender.
Whenever three or more creatures you control attack or block, each creature you control assigns combat damage equal to its toughness rather than its power this turn.

Once each turn, when you spend mana from a Desert to cast a spell, create a 1/1 red and green Bird creature token with flying and vigilance.
Whenever three or more creatures you control deal combat damage to a player, untap each land you control.

Flying
Whenever Buzzing Flitter attacks, you may pay {G}. If you do, untap target permanent.

Archive X (As this enters, shuffle the top X cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, create two 1/1 green Insect creature tokens.

[+1]: Create a green enchantment token named Swarm with “At the beginning of your end step, create a 1/1 green Insect creature token.”
[–2]: Create a green enchantment token named Survive with “Whenever a creature you control dies, you gain life equal to its power.”
[–4]: Create a green enchantment token named Scrounge with “Whenever a creature you control enters, draw a card.”

Bwema, the Ruthless enters with your choice of two different counters on it from among menace, first strike, vigilance, and lifelink.

Haste
Sacrifice another creature: Bygone Aristocrat gains indestructible until end of turn.

Equipped creature gets +1/+2.
At the beginning of your end step, if Bygone Blade isn't attached to a creature, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)
Equip {2}

({T}: Add {W}.)
Bygone Guardian enters tapped.
Vigilance
{2}{W}{W}: Bygone Guardian becomes a creature in addition to its other types until end of turn.

Whenever Bygone Wreck deals combat damage to a player, you may sacrifice it. If you do, create five Treasure tokens.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

When Byron, Unlikely Hero enters, put a +1/+1 counter on each other Citizen or Peasant you control.
Whenever a nontoken creature you control with a +1/+1 counter on it dies, create a 1/1 white Peasant creature token.

Flying
When Byte Bug enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Whenever Byway Bruiser enters or leaves the battlefield, you may have it deal 3 damage to any target.

Menace, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Flying
Whenever you gain life, each opponent loses 1 life.

When Cabinet of Curiosities enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Defender, reach
Sacrifice Cackling Jack: It deals 3 damage to any target.

Haste
Revive {3}{R} ({3}{R}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Whenever one or more cards are put into an opponent's graveyard from their hand or library, Cackling Tormentor deals 2 damage to any target.

Trample
Whenever Cacophonous Demon deals combat damage to a player or planeswalker, you may exile target artifact or enchantment.
Whenever a creature deals damage to you, tap that creature. It becomes an enchantment in addition to its other types.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature you don't control blocks, Cadalon Chemist deals 1 damage to that creature.