msem-instigator

Flying, haste
Whenever Ma'Long deals combat damage to a player, draw a card, then add that much mana in any combination of {U} and/or {R}. Until end of turn, you don't lose this mana as steps and phases end.
Instant and sorcery cards in your hand have showcase. The showcase cost is equal to the card's mana cost plus {2}. (If you cast it for its showcase cost, create a 1/1 red Bard creature token that can't block and exile that card. Whenever the Bard attacks, you may cast a free copy of the exiled card.)

When Maaru, Tomb Guardian enters, create three Treasure tokens.
Each Treasure you control is an artifact creature with power and toughness each equal to the number of Treasures you control.

Trample
When Magmatic Ravager enters, two target lands you control don't untap during your next untap step.

At the beginning of your upkeep, if five or more instant and/or sorcery cards are in your graveyard, return target instant or sorcery card at random from your graveyard to your hand.

Haste (This creature can attack and {T} as soon as it comes under your control.)
Double strike (This creature deals both first-strike and regular combat damage.)

When Manglehorn Hunter enters, draw a card and you lose 1 life.

Flying
Whenever you attack, create two 1/1 white Human creature tokens that are tapped and attacking. Creatures you control get +1/+1 until end of turn.
Fleeting {2}{W}{W} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

When Marauding Goliath becomes blocked by a creature with power 1 or less, sacrifice it at end of combat.

[+1]: Exile up to one target tapped creature.
[–2]: Create a 4/4 white Angel creature token with flying.
[–3]: Destroy all creatures. You gain 1 life for each creature destroyed this way.
[–7]: You get an emblem with “At the beginning of each end step, you gain life equal to twice the life you've lost this turn.”

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

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

Flying

Menace
Whenever Masoh enters or attacks, each opponent that has more than four cards in hand discards cards equal to the difference. Then if you have fewer than four cards in hand, draw cards equal to the difference.

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.

Indestructible (Damage and effects that say “destroy” don't destroy this creature.)

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.

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

Flash
Flying
When Mending Valkyrie enters, choose target permanent you own or permanent card with mana value 3 or less in your graveyard. You may return it to your hand.

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.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

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.

This spell costs {1} less to cast if you control a Warrior.

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.

[+1]: The next instant or sorcery spell you cast this turn costs {1} less to cast.
[–4]: Until end of turn, whenever you cast an instant or sorcery spell, Merkurio deals 2 damage to any target.
[–8]: Exile the top seven cards of your library. You may cast any number of instant and sorcery cards from among them without paying their mana costs.

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.)