msem-instigator

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Griffin Skycaller enters, target creature you control gets +1/+1 and gains flying until end of turn.

Haste
{2}{W}, {T}: Hair-Trigger Marshall deals 2 damage to target blocking creature.

{R}, {T}: Sandbluff Slinger deals 1 damage to any target.
Quickdraw {1}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {1}{R}.)

When Judge of Clans enters, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature.” attached to target creature.)
{T}: Add one mana of any color.

Destroy target creature with power 4 or greater.

When Blazeblade Sergeant enters, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
Whenever an Aura you control enters, target creature you control gains first strike until end of turn.

Activated abilities cost {1} more to activate unless they're mana abilities.

When Army Guide dies, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{2}{G}{W}, Sacrifice Army Guide: Exile target noncreature, nonland permanent. Activate only as a sorcery.

When Scrivener of Sha'Iv enters, draw a card and adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)

Flying
Whenever an artifact you control enters, you may activate one of its activated abilities without paying its cost.

Archive 5 (As this enters the battlefield, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
When you get your eighth research counter, exile Turin's Study, then you may cast any number of nonland cards from the archived library without paying their mana costs.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{T}: Salvage a creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

When Plane-Traversal Guide enters, you may exile a card you own from outside the game. When Plane-Traversal Guide is no longer on the battlefield, put the exiled card into your hand.

Enchant creature
Enchanted creature gets +2/+2.
Sacrifice Steady Reminiscence: Enchanted creature gains indestructible until end of turn.

When Bridled Narwhal enters, you gain 5 life.

When Furnished Ghul dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Rotrider Renegade can't block or be blocked.
{1}{B}: Rotrider Renegade gets +1/+1 until end of turn.
Dash—Reveal a Rogue card from your hand, Pay 2 life (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Griffin Country enters with a feather counter on it.
Creatures with flying you control get +1/+1.
{U}, Remove a feather counter from Griffin Country: Put a flying counter on target creature you control.
{2}{U}, Remove a feather counter from Griffin Country: Search your library for a creature card with flying, reveal it, put it into your hand, then shuffle.

When Mental Supremacist enters, choose target creature you don't control. That creature has base power and toughness 1/1 and loses all abilities for as long as you control Mental Supremacist.

Creatures your opponents control have haste.

{T}, Sacrifice Renewal Grove: Search your library for a basic land card, put it onto the battlefield, then shuffle. If Renewal Grove entered since your last upkeep, that land doesn't untap during your next untap step.

Choose a permanent type. Permanents you control of that type gain hexproof until end of turn.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, permanents you control gain hexproof until end of turn instead.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{B}{B}: Choose any number of other nontoken creatures you control. Whenever one of those creatures dies this turn, create a token that's a copy of that creature, except it has no mana cost.

Whenever you cast an instant or sorcery spell, you may pay {1}. If you do, choose one—
• Draw a card, then discard a card.
• Tap target creature.
• Target creature gains flying until end of turn.
• Target player mills two cards.

When Improvisionist enters, if it was the second spell you cast this turn, exile the top card of your library. You may play that card until the end of your next turn.