msem-instigator

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.)
Creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of combat on your turn, target creature you control with mana value 3 or less can't be blocked this turn. If Streetwise Investigator has two or more counters on it, that creature gains vigilance until end of turn.

Poisonous 4 (Whenever this creature deals combat damage to a player, that player gets four poison counters.)
At the beginning of combat on each of your turns, if an opponent is poisoned, creatures you control gain trample until end of turn.

Spellwoven Monster can't be the target of spells or abilities in any zone.
As you cast an instant or sorcery spell, reveal cards from the bottom of your library until you reveal an instant or sorcery card. You may add that card's effects to that spell. Then shuffle.

Whenever Paomar Greatheart attacks, put a trample counter on target attacking creature in its pack. (Two or more creatures you control with equal power are in a pack.)

Enchant land (Target a land as you cast this. This card enters attached to that land.)
Enchanted land has “{T}: Add one mana of any color” and “At the beginning of each upkeep, untap this land.”

Choose one —
• Target creature gains indestructible until end of turn.
• Destroy target creature with toughness 4 or greater.

Exile target creature or planeswalker. Its controller may search their library for a creature or planeswalker card and reveal it, then shuffle and put that card on top.

Flash
When Wormwood's Agent dies, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Create a 2/2 red Dragon creature token with flying and haste.
Whenever a nontoken Dragon you control attacks, you may return Flynn's Wonder from your graveyard to your hand.

Tears of Tizuma enters tapped.
{T}: Add {U}.
Whenever Tears of Tizuma becomes tapped for mana, target player mills a card.

Engage (This creature must be blocked each combat if able.)
Whenever Blade of Fretport becomes blocked by a creature, Blade of Fretport deals 1 damage to that creature.

Trample
When Moranai Outriders enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.

Flying, haste
Miyoga Flameweaver can't block.
Whenever Miyoga Flameweaver attacks, exile the top card of your library. You may play that card until end of turn.

Reach
Spined Tarantula gets +1/+1 for each creature with flying your opponents control.

{T}, Sacrifice an artifact or creature: Each opponent loses 1 life and you gain 1 life.

Invigorate 1 three times. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)

CySec Infiltrator can't be blocked except by enchantment creatures.
Whenever CySec Infiltrator attacks, create a Function token with “Target player loses 2 life and you gain 2 life.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

When Peddler of Commonwares enters, you may draw a card. If you do, discard a card.

All creatures able to block Raiun Bay Merchant do so.

Survivors you control have haste.

When Truthseeker Prodigy enters, amass Soldiers 2. Then target player mills X cards, where X is the amassed Army's power. (To amass Soldiers 2, put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control an Army, create a 0/0 black Soldier Army creature token first.)

Create four 1/1 red and white Warrior creature tokens.

You may have Icefang Wurm assign its combat damage as though it weren't blocked.
{4}{G}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature you control with flying attacks, it gets +1/+1 until end of turn.