msem-instigator

[+1]: Draw a card. Each player loses 1 life.
[–2]: Create two 1/1 black Bat creature tokens with flying and lifelink.
[–3]: Target creature gets -13/-13 until end of turn. You control abilities of that creature that trigger this turn.

Play with the top card of your library revealed.
You may cast creature spells from the top of your library. You may cast Centaur spells this way without paying their mana costs.

You may put a permanent card from your hand onto the battlefield. If it's a planeswalker, it enters with five loyalty counters rather than any other amount, and you may activate its loyalty abilities this turn any time you could cast an instant.

Exile target nonland permanent.

Bestow {1}{G}{W}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Krikam, the Wanderer and enchanted creature have protection from nonenchanted creatures.

As long as an opponent has one or fewer cards in hand, Valdez gets +2/+0 and has menace.

Whenever you cast a spell from anywhere other than your hand, return Ruthless Bakhtak from your graveyard to your hand.

When Second-Stage Actress enters, audition for white. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Cleric Role giving 2/2 and lifelink. Roles replace older ones.)
As long as it's your turn, Second-Stage Actress has first strike.

Flash
Motivate 7 (When this creature enters, you may motivate target creature with less power than this by putting seven +1/+1 counters on it.)

When Abaran enters, put a -1/-1 counter on up to one target creature.
At the beginning of your upkeep, if you control a creature with the greatest toughness among creatures on the battlefield, each opponent discards a card.

When Batrest's Forgemaster enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
Whenever Batrest's Forgemaster attacks, Equipment spells you cast this turn cost {2} less to cast.

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.

Whenever Fox of the Mushroom Forest enters or deals combat damage to a player, its activated abilities cost {W} less to activate until your next turn.
{W}, Sacrifice Fox of the Mushroom Forest: Counter target noncreature spell unless its controller pays {2}.

When Festival Celebrants enters, put a +1/+1 counter on each creature you control.

Whenever you cast an Azra spell, mill three cards.
Whenever you cast a Demon spell, you may return an Azra card with lesser mana value than that spell from your graveyard to the battlefield.

Discard any number of cards, then draw that many cards plus one. When you do, return target nonland permanent card with mana value less than or equal to than the number of cards discarded this way from your graveyard to the battlefield tapped.

If a spell, ability, or creature an opponent controls would deal 4 or more damage to you or cause you to lose 4 or more life, you lose 4 life instead. (Damage won't be dealt.)

Discard a card: Search your library for a card with the same mana value as the discarded card, reveal it, put it into your hand, then shuffle. Activate only as a sorcery and only once each turn.

Colorless creatures you control get +1/+1.

Flying
Ward—Pay 4 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 4 life.)
Whenever you cast an instant spell, draw a card.
Whenever you cast a sorcery spell, Typhoon Terror deals 2 damage to any target.

Flying
When Foul Vulture enters, create a 1/1 red Hound creature token.
Foul Vulture gets +1/+0 as long as a creature you controlled died this turn.

Counter target spell.
{1}{U}, Exile Refute from your graveyard: Draw a card.

Put target creature card from a graveyard onto the battlefield under your control. If that card was put into that graveyard this turn, it enters with an additional +1/+1 counter on it.

Chamber of Splendor enters tapped.
When Chamber of Splendor enters, you may pay {1}. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{T}: Add {C}.