msem-instigator

Look at the top three cards of your library. Put one of them into your hand. Put Lost in Deep Storage and the rest on the bottom of your library in any order.

Exile target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Enchant creature
When Lost to the Elements enters, if enchanted creature isn't in a pack, tap it. (Two or more creatures with the same controller and equal power are in a pack.)
Enchanted creature doesn't untap during its controller's untap step.

Reveal the top card of your library. Draw X cards, where X is that card's mana value.

Put a +1/+1 counter on target creature. It can't be blocked this turn.(Cast a copy of this spell once while this creature is on the battlefield.)

Draw a card.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Whenever you cycle a card, scry 1. (Do this before you draw.)
{W}{U}{B}{R}{G}, Sacrifice Maelstromancy: Return up to three target cards with cycling abilities from your graveyard to your hand.

Search your library for a cryptic card, reveal it, put it into your hand, then shuffle. (Artifacts, enchantments, and modal spells are cryptic.)

Choose two —
• Target player creates a 1/1 blue Wizard creature token with prowess.
• Target player draws two cards, then discards two cards.
• Tap up to two target creatures.
• Target creature or player gains hexproof until end of turn.

Equipped creature gets +2/+1 and has flying.
Equip Wizard or Shaman {2}
Equip {4}

Target creature you control gains hexproof until end of turn. Scry 1.

Tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.
Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Counter target spell. If a permanent spell is countered this way, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)

[+1]: Scry 2. Whenever one or more creatures you control deal combat damage to a player this turn, draw a card.
[–2]: Create a token that's a copy of target creature you control, except the token is 4/4 and has vigilance.
[–7]: You get an emblem with “At the beginning of your draw step, draw two additional cards” and “Creatures you control get +1/+1 for each card you've drawn this turn.”

Choose one —
• Counter target spell unless its controller pays {2}.
• Change the target of target spell with a single target unless that spell's controller pays {2}.

Deception {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
As long as it's your turn, Marilye is a 3/2 Elf Rogue creature with hexproof and indestructible.
[+1]: Tap target permanent. It doesn't untap during its controller's next untap step.
[–2]: Exile the top five cards of target opponent's library. You may cast any number of cards exiled this way with total mana value less than or equal to the amount of damage dealt to them this turn without paying their mana costs.

You may spend mana as if it was mana of any color to cast cards exiled with Marilye.
[+1]: Exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards.
[–3]: Exile target creature. You may cast that card. If you don't, return it to its owner's hand.
[–7]: Gain control of up to five target nonland permanents.

Exile any number of target creatures. For each creature exiled this way, its controller creates a 3/2 green Crocodile creature token with trample.

When Marshcroaker Coaching enters, create three 1/1 blue Frog creature tokens.
Frogs you control have “{T}: Target creature gains flying until end of turn.”

Gain control of target creature with power X or less.

Shuffle the cards from your hand into your library, then draw that many cards.
Draw a card.

Enchant creature
You control enchanted creature.

Codex — Unraveling; Unraveling; Unrelenting; Unrelenting; Mindrip; Swipe Secrets. (As this enters, conjure its contents into a shuffled face-up additional library.)
Flash
When Mei's Collection enters, draw a card from its codex.

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

Enchant player
Whenever enchanted player casts a spell, they reveal cards from the top of their library until they reveal a card that shares a type with that spell, then puts all cards revealed this way into their graveyard.