msem-instigator

{X}{U}{U}: Marine Monster can't be blocked by creatures with mana value X or less this turn.

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

Whenever Marshback Knights becomes the target of a spell or ability an opponent controls, counter it unless they pay {3}.
{1}{U}: Marshback Knights gains flying until end of turn.

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.”

Flying
When Marshcroaker Drake enters, you may return target creature with power 2 or less to its owner's hand.

Lionize {2}{U} ({2}{U}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Whenever this creature deals combat damage to a player, draw that many cards.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Martoob Watershaper enters, tap target creature. It doesn't untap during its controller's next untap step.

Flash
You may cast Angel and Nephilim spells as though they had flash.

Masked Impersonator can't be blocked.
Art of war — At the beginning of your end step, if Masked Impersonator dealt damage to an opponent this turn, you may have it become a copy of target creature you control except it has this ability.

Whenever another creature enters, Masquerading Bohemian becomes a copy of that creature except it's a Noble in addition to its other types and it has this ability.

Master Assassin can't be blocked by creatures with odd mana values. (Zero is even. This creature's mana value is 2.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Master Assassin. You may have it phase out.

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 Master Negotiator enters, you may gain control of target nonland permanent an opponent controls with mana value 2 or less. If you do, its controller may draw a card. Otherwise, you draw a card.

Flying
Whenever you cast an instant or sorcery spell from your hand, you may cast an instant or sorcery card with mana value less than or equal to that spell's mana value from your graveyard without paying its mana cost. Exile that card instead of putting it into your graveyard as it resolves.

Instant and sorcery spells you cast cost {1} less to cast.
{U}, {T}, Exile three instant and/or sorcery cards from your graveyard: Draw a card.

As long as you control an Island, you may cast this spell as a copy of any creature on the battlefield. (This includes casting cost.)

You may choose not to untap Master of Minds during your untap step.
{T}: Gain control of target creature with mana value X or less for as long as Master of Minds remains tapped, where X is the number of Islands you control.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, you may switch Master of Tranquility's power and toughness until end of turn.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Master of Winds or another creature with flying you control enters, you may draw a card.

When Master of the Abyss enters, draw two cards, then discard a card.
{2}{U}{U}, {T}, Discard two cards: Create an X/X black Horror creature token, where X is the number of cards in your graveyard.

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.

Colossal 4—{5}{U}{U}{U} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{U}{U}{U} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever Megalokraken enters or attacks, reveal the top X cards of your library, where X is Megalokraken's power. You may cast a noncreature spell with mana value X or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

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.