msem-instigator

Whenever you cast a spell, if it isn't your main phase, scry 1.

Flying
Whenever you cast a noncreature spell, note its mana value.
When Strix of Dark Omens dies, draw a card and create a 1/1 blue Bird creature token with flying for each different number noted with it.

Flying
At the beginning of your upkeep, you may pay {1}. If you do, put a +1/+1 counter on Swarm of the Dispossessed.
Sacrifice Swarm of the Dispossessed: Counter target spell with mana value X, where X is the number of +1/+1 counters on Swarm of the Dispossessed.

Whenever you scry, Taker of Tithes gets +1/+0 until end of turn and can't be blocked this turn.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Temple Instructor enters, return target creature to its owner's hand.

Flying
{T}: Target land you control becomes the basic land type of your choice until end of turn.

{T}: Draw a card. Activate only if Theoretical Scholar is embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Flying
Tianyuren Skycharter has hexproof as long as you control a storied permanent. (Enchantments and legendary permanents are storied.)

Lionize {1}{U} ({1}{U}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Sacrifice this creature: Counter target instant or sorcery spell unless its controller pays {X}, where X is this creature's power.

When Truffle Snuffer enters, mill three cards. When you do, choose one —
• Return an instant or sorcery card put into your graveyard this way to your hand.
• Put two +1/+1 counters on Truffle Snuffer.

Prowess
When Tuesday's First Victim dies, audition for blue. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Ulek Windrider envisions an instant or sorcery card, it gets +1/+0 and gains flying until end of turn.

Unassuming Waif can't be blocked.
Unassuming Waif gets +1/+0 for each other Warrior you control.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever a creature deals combat damage to a player, if it was encouraged by Unbeholden Navigator this turn, draw a card.

Whenever you cast a noncreature spell, create a 1/1 colorless Construct artifact creature token.

Discard a card: Unseen Maniac gets +1/+1 and can't be blocked this turn.
Whenever Unseen Maniac deals combat damage to a player, draw a card.

Flash
When Veilborn Meddler enters, counter target spell if its mana value is less than or equal to Veilborn Meddler's power.
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Veilborn Meddler.

When a creature you control scavenges Wanderer of Many, create a token that's a copy of that creature. Put a +1/+1 counter on the copy.
Scavenge {3}{U} ({3}{U}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

When Whisper Collector dies, draw a card.

Flying
{U}, Sacrifice Willow Spirit: Counter target spell or ability that targets you or a creature you control.

Flying
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Rapport — Whenever Witch's Apprentice and at least one other creature you control become tapped, Witch's Apprentice gets +1/+1 until end of turn, then scry 1.

When Wizened Calligrapher enters, you may search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top of it.

At the beginning of your upkeep, you may pay 2 life. If you do, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Wither (This deals damage to creatures in the form of -1/-1 counters.)
When Abyssal Familiar dies, it deals 1 damage to you and to any target.