msem-instigator

Exile target creature, then return that card to the battlefield under its owners' control.

Vanishing 4 (This creature enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Remove a time counter from Tideshift Elemental: You may tap or untap target creature.

For each creature, its owner puts it on the top or bottom of their library.

Enchant nonland permanent
Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
You control enchanted permanent.

Look at the top three cards of your library. Put one of them into your hand, one on top of your library, and one on the bottom of your library.
Reprise {1}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Risen Looter enters, if it engorged a noncreature, nonland card, draw a card, then discard a card.

Put four time counters on target nonland permanent. If it doesn't have vanishing, it gains vanishing. (At the beginning of your upkeep, remove a time counter from that permanent. When the last is removed, sacrifice it.)

Return target nonland permanent to its owner's hand.
Reprise {2}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Draw three cards.
Reprise {5}{U}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Whenever Merfolk Visionary or another Merfolk creature you control enters, scry 2. (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.)

{T}: Draw a card, then discard a card.

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.

Draw a card for each instant and sorcery card in your graveyard.

Flash
When Master Echomage enters, you may cast target instant or sorcery card from your graveyard with mana value X or less without paying its mana cost, where X is the number of Wizards you control. Exile that card instead of putting it into your graveyard as it resolves.

When Lafterii Augur enters, reveal the top card of your library. If it's an instant or sorcery card, put it into your hand. Otherwise, put it into your graveyard.

Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Hapless Chronomancer dies, if it had no time counters on it, return target instant or sorcery card from your graveyard to your hand.

Put target creature on top of its owner's library.

Reprise {3}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)
Scry 3, then draw a card.

Flying
Vanishing (At the beginning of your upkeep, remove a time counter from this permanent. When the last is removed, sacrifice it.)
Ficklewing Elemental enters with a time counter on it for each card in your hand.

When Ethereal Spellmaster enters, if it was cast, you may search your library for an instant or sorcery card with mana value 3 or less and cast it without paying its mana cost. If you do, shuffle your library. (If it has X in its mana cost, X is 0.)

Draw a card.
Reprise {2} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Counter target spell. If that spell is countered this way, draw a card, then discard a card.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Deadland Summoner dies, you may put the card it engorged into your hand. If that card is an instant or sorcery card, you may instead cast it without paying its mana cost.

At the beginning of your upkeep, mill a card.
Whenever a creature card is put into your graveyard from your library, you may exile it. If you do, create a 2/2 black Zombie creature token.