msem-instigator

Create two tokens that are copies of target creature you control, except the tokens aren't legendary if the creature is legendary. Those creatures gain haste until end of turn.

Destroy all creatures. For each creature destroyed this way, its controller draws a card.

Creatures you control attacking cause abilities of that creature to trigger as though it entered.
Once each turn, when you attack, you may pay {1}{R/W}. When you do, untap target attacking creature. After this phase, there is an additional combat phase.

Flash
When Master of Disorientation enters, you may choose new targets for target instant or sorcery spell. Then proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

You can't cast more than one spell each turn.
Whenever you cast a spell, draw a card.

When Mausoleum Suffragan enters, create a white and black Aura enchantment token named Pale Shroud attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+1 and has lifelink.”
Whenever an artifact or enchantment you control enters, each opponent loses 1 life.

Creatures you control lose poisonous and can't have or gain poisonous.
Snakes you control deal damage to players in the form of poison counters.

Trample, hexproof
When Maw of a Thousand Worlds enters, distribute X +1/+1 counters among creatures you control, where X is the number of differently named lands you control.
When Maw of a Thousand Worlds dies, you may remove any number of counters from among permanents you control. For each counter removed this way, draw a card.

Whenever Mawdryk, Endrison Warden or another nontoken Elf creature you control enters, create a 1/1 green Elf Druid creature token.
{B}{G}, Sacrifice two Elves: Destroy target non-Elf creature.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Recursive — As long as Mayar, Nullcrowned is a Curse, they have all nonrecursive abilities of other Curses and creatures with breach you control.
Pay 3 life: Target enchantment creature gains haste and menace until end of turn.

This spell can't be countered.
Flying, haste
Mayu, the Endless Flow gets +2/+2 for each spell you've cast this turn.

At the beginning of combat on your turn, if you cast an enchantment spell, an instant spell, and a sorcery spell this turn, create two 3/3 red Shark enchantment creature tokens. You may have any number of those tokens gain haste. If you do, sacrifice the tokens you chose at end of combat.

{W}{B}, Pay X life: Return target creature card with mana value X from your graveyard to the battlefield with a finality counter on it. Activate only as a sorcery and only once each turn.
{W}{B}, Pay 3 life: Return Mehr's Last Captain from your graveyard to the battlefield with a finality counter on it.

Whenever a player discards a card, you may draw a card and put a loyalty counter on Mei Liva, the Broken.
[0]: Target permanent's controller sacrifices it unless they discard two cards.
[–1]: Each opponent loses X life and you gain X life, where X is the number of cards in your hand.
[–3]: Target player chooses a card in their hand, then discards the rest.

[+1]: Search each player's graveyard, hand, and library for any number of cards with the same name as target nonbasic card in a graveyard and exile them. Then each player shuffles.
[–2]: Each player draws two cards, then each opponent exiles two cards at random from their hand.
[–5]: You may cast a card exiled with Mei Liva without paying its mana cost.

[+2]: Each opponent loses 2 life. Scry 2.
[–3]: Return target creature to its owner's hand. That player discards a card.
[–6]: You get an emblem with “Whenever a player discards a card, you may cast it without paying its mana cost.”

[+1]: Draw a card unless an opponent discards a card.
[–3]: Gain control of target creature until the end of your next turn.
[–6]: Choose up to four cards in graveyards. You may play those cards without paying their mana costs.

Lifelink
Creatures can't be sacrificed.
{1}: Add {G}, {U}, or {R}. Spend this mana only to cast a Human spell.

Flash
Flying
When Mellan enters, exile up to one other target nonland permanent with mana value equal to or less than the number of creatures you control with flying until Mellan leaves the battlefield.

(Choose only one work as a sorcery to add its ability.)
When Memorial Plaza enters, create two 1/1 colorless Spirit creature tokens with flying.
{2}{W}: The Warrior
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
{1}{B}: Rhapsody in Black
At the beginning of your end step, you may sacrifice a creature. If you do, draw a card.

Reverberate {2}{U}{R} (When you cast this spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)
Exile target instant or sorcery card from your graveyard. You may cast a copy of that card without paying its mana cost.

At the beginning of each end step, if a creature left the battlefield this turn, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)
{2}{W}{U}: When target creature dies this turn, return that card to its owner's hand.

Whenever Memory of Fatalism dies or you cast a noncreature spell, each opponent loses 2 life and you gain 2 life.
{4}: Put Memory of Fatalism from your graveyard on top of your library.

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.