msem-instigator

Target opponent reveals their hand, exiles each nonland card from it, then conjures a card named Data-Point into their hand for each card exiled this way. (It's a sorcery that costs {2} with “Draw a card.”)

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.

Draw X cards and you gain X life, where X is the number of card types among permanents you control.

Lifelink
If a source would deal damage to a player, you may prevent X of that damage, where X is the number of +1/+1 counters on Mending Caretaker.

Whenever one or more creatures attack Menes, the Great Pyramid, create a tapped 2/3 black Mummy creature token.
[+1]: You get an emblem with “Black creatures you control get +1/+1.”
[–3]: Exile target creature card from a graveyard. Create a tapped token that's a copy of it except it's a black Mummy.

Destroy all creatures without flying.

Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)
[+2]: Exile the top two cards of your library. Until end of turn, you may play one card exiled with this permanent.
[+1]: Exile up to two cards from your hand, then draw that many cards.
[–3]: Menna, Servant to None deals 3 damage to up to one target player and up to one target creature or planeswalker.

Flash
When Mennin Pack enters, each opponent loses 1 life.
When Mennin Pack dies, each opponent discards a card.

Create X 1/1 black Goblin creature tokens. Gain control of target permanent with mana value X or less until end of turn. Untap it. It gains haste until end of turn.

Flash
Enchant instant or sorcery spell
Enchanted spell's text box is “This spell deals 3 damage to you.”
{4}{U}{U}{R}{R}: Return Mental Meltdown from your graveyard to the battlefield.

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.

Other Elementals you control get +2/+2.
Whenever one or more Elementals you control attack, tap up to one target creature you don't control.

Whenever another creature with power 4 or greater you control enters, you may draw a card.

{T}: Add {C}.
Satrapies you control enter untapped.

Flying, vigilance
Prevent all damage Merciful Yuroda would deal to creatures.

Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)
Whenever Merciless Exiled deals combat damage to a player, scry 2.

Whenever one or more creatures deal combat damage to you, exile one of those creatures.
You may cast cards exiled with Merciless Mirror and may spend mana as though it were mana of any color to cast those spells.

{2}{G/U}{G/U}, {T}: Untap each non-Lizard permanent you control.

This spell can't be countered.
Whenever Meren, Bane of the Cairns attacks, exile target creature card from your graveyard. You may cast that card for as long as it remains exiled by sacrificing a creature in addition to paying its other costs.

Choose two —
• Counter target spell unless its controller pays {6}.
• Target player draws two cards, then discards a card.
• Creatures target player doesn't control get -3/-0 until end of turn.
• Exile up to two target creatures, then return those cards to the battlefield under their owners' control.

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 Merrow Legendmaker attacks, look at the top five cards of your library. You may reveal an Aura, Aurashaper, or Equipment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Survivors you control get +3/+3.

Enchant creature
When Mesmerizing Shimmer enters, untap enchanted creature. It gains haste until end of turn.
You control enchanted creature.
Mirage {2}{U}{R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Flying
When Messenger of the Heavens enters, surveil 1.
Whenever Messenger of the Heavens deals combat damage to a player, exile any number of target creatures in its pack, then return them to the battlefield under your control. (Two or more creatures you control with equal power are in a pack.)