msem-instigator

Flying
Whenever Haunting Horseman deals combat damage to a player, that player discards a card.

Flying
When Djinni of Whispers enters, untap up to three Islands.

Menace, haste
Whenever Aiel's Fury attacks, scry 2, then reveal the top card of your library. Aiel's Fury gets +X/+0 until end of turn, where X is that card's mana value.

Destroy target artifact or enchantment. Scry 2.

Untap target creature you control. It gets +1/+4 and gains hexproof and reach until end of turn.

Whenever another creature enters, Brutish Champion fights that creature.

Sacrifice Amateur Auteur: Destroy target enchantment.

Flash
Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)

Return target creature or planeswalker card from your graveyard to the battlefield. If that card was a creature, it's an Actor in addition to its other types.

(Choose only one work as a sorcery to add its ability.)
When Seto's Private Collection enters, creatures you control get +2/+1 until end of turn.
{1}{R}: Bloodline
Attacking creatures you control have first strike.
{2}{W}: Hope's Savior
Attacking creatures you control have lifelink.

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 you cast a white spell, creatures you control get +1/+0 until end of turn.
Whenever you cast a blue spell, draw a card, then discard a card.

If you would draw one or more cards, instead you may draw that many cards plus one, then discard a card.
As long as ten or more cards are in your graveyard, noncreature spells you cast cost {1} less to cast.

Return target creature card from your graveyard to your hand.
Inscribe {3}{B} ({3}{B}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Choose one —
• Destroy target monocolored creature.
• Ria-Demian Charm deals 2 damage to each creature.
• Each player discards two cards and loses 2 life.

Each opponent mills half their library, rounded up. When they do, return target creature card from a graveyard to the battlefield under your control.

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

When Curator of Cures 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, you gain 1 life.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Return target creature card from your graveyard to the battlefield.
5 | It gains vigilance, trample, lifelink, indestructible, and haste until end of turn.

Resolute — Skerry Serpent must be blocked if able as long as its power is greater than its base power.

When Deputy Gibem enters, post a bounty on each creature and each planeswalker. (Put a bounty counter on those permanents. Each of them have “When this permanent dies, each opponent draws a card” as long as it has a bounty counter on it.)

Flying, haste
Whenever Guardian of the Devout attacks or blocks, other creatures you control gain indestructible until end of turn.

Flying
Whenever an opponent discards one or more cards, fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

All creatures get -2/-2 until end of turn. At the beginning of the next end step, if three or more creatures died this turn, create two tapped Treasure tokens.

Scry 2, then draw two cards. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)