msem-instigator

Prowess
Landfall — Whenever a land you control enters, create a 1/1 green, blue, and red Elf Scout creature token with prowess.

Enchant creature
Enchanted creature has double strike.
Mirage {1}{W} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{4}{B}{B}, {T}, Sacrifice Abalone Abomination: Create an X/X black Horror creature token, where X is the number of cards in your graveyard.

Menace, haste
Whenever Manic River-Fishers attacks, you may search defending player's library for an instant or sorcery card that shares a name with a card in their graveyard and cast it without paying its mana cost. That player shuffles.

Trample
Harmony — Avalanche Drummer deals 1 damage to any target.
When Avalanche Drummer enters, harmonize. (Trigger up to one harmony of a permanent you control.)

Choose one—
• Destroy target permanent with mana value 2.
• Return target permanent card from a graveyard to its owner's hand.
Exile Veil's Recovery.

Firebolt deals 2 damage to any target.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sacrifice a creature: Until end of turn, Advocate of Foibles gets +2/+0 and becomes a Demon in addition to its other types.
{1}{B}{G}: Amass Soldiers 1. (Put a +1/+1 counter on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{X}{R}: Hearth Dweller gets +X/+0 until end of turn.

I, II — Target creature you control gets +2/+0 and gains menace until end of turn.
Discovery — Attacking creatures you control get +2/+0 and have menace.

Target creature gets +1/+1 and gains distorted until end of turn. (It can be blocked by tapped creatures but not untapped creatures.)
Put the bottom card of your library into your hand.

At the beginning of your end step, put a -1/-1 counter on each creature you control.
[+1]: Create two 2/2 black Zombie creature tokens.
[0]: Whenever a creature dies this turn, you draw a card and you lose 1 life.
[–4]: Target opponent gets an emblem with “At the beginning of your end step, put a -1/-1 counter on each creature you control.”

As long as equipped creature has power 3 or less, it can't be blocked and it can't be the target of spells and abilities you don't control.
Equip {1}
Whenever Ring of Souls becomes attached to a creature, an opponent of your choice may create a 2/2 black Spirit creature token.

Predatory Abomination has deathtouch and lifelink as long as you control another Horror.

Whenever Slaffield Workgate or another enchantment you control enters, create a 0/2 white Ox creature token.
{3}{W}: Return another target enchantment you control to its owner's hand.

If an effect you control other than a siphon ability would put a counter on a permanent, you may put a flying, vigilance, or stun counter on that permanent instead.

Whenever you cast a noncreature spell, you may put a progress counter on Wunderkind Devising.
[progress 1+] At the beginning of your upkeep, reveal the top three cards of your library. Put each artifact card from among them into your hand and the rest into your graveyard.
[progress 4+] Artifacts you control are artifact creatures with base power and toughness 5/5.
Artifacts you control are artifact creatures with base power and toughness 5/5.

At the beginning of each upkeep you may pay {W}. If you do, tap target creature.

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

Flying
Whenever Haunter of the Deadlands attacks, Spirit creatures you control get +1/+1 until end of turn.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would be put into a graveyard or not resolve.)
Return all creatures to their owners' hands. Each player discards two cards.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Marked creatures your opponents control lose all abilities.

When Barbarian Intimidator enters, target creature can't block this turn.
When Barbarian Intimidator enters, prevent all combat damage that would be dealt to target creature this turn.

Exile the top two cards of your library. Until the end of your next turn, you may play those cards. (If you cast a spell this way, you still pay its costs. You can play a land this way only if you have an available land play remaining.)

{3}{W}: Tap target creature with power 4 or greater.