msem-instigator

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Master of Ancient Ways mentors a creature, that creature gains double strike until end of turn.

When Master of Marble Row enters, choose one —
• Create a colorless Monument artifact token with “Creatures you control get +1/+1.”
• Create a white Cloister enchantment token with “When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.”

You may activate equip abilities any time you could cast an instant if you pay an additional {1} to activate them.
Armed — Equipped creatures you control get +1/+1 as long as Master of Steel is equipped.

Whenever you cast a spell, if it isn't your main phase, choose one. This ability triggers only once each turn.
• Put a +1/+1 counter on Master of Three Paths.
• Tap target creature.
• Master of Three Paths phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Enchant creature
Enchanted creature has defender.

Enchant creature
Enchanted creature gets +1/+1.
{W}: Enchanted creature gains vigilance until end of turn.
{1}{W}: Enchanted creature gains first strike until end of turn.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever an experience ability puts a +1/+1 counter on a creature you control, put a +1/+1 counter on that creature.

When Matron of Machines dies, put a +1/+1 counter on up to one target creature.
{3}{W}, Exile Matron of Machines from your graveyard: Create two 1/1 colorless Construct artifact creature tokens. Activate only as a sorcery.

First strike
Mauling Mother gets +1/+1 for each other creature you control.

I, II — Put a +1/+1 counter on target creature you control.
Discovery — Creatures you control with +1/+1 counters on them have lifelink.

When Meletis Oracle enters, scry 1, then draw a card.

Heroic — Whenever you cast a spell that targets Meletis Stargazer, scry 2.
{T}: Look at the top card of your library. If it's a permanent card with mana value 3 or less, you may reveal it and put it into your hand.

Whenever Melodious Musician attacks, tap target creature an opponent controls.

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.

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.

Choose one —
• Target creature gets +0/+3 until end of turn.
• Target creature gains flying and lifelink until end of turn.

Destroy all creatures without flying.

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.

As Mercantile Accords enters, choose a number.
Whenever an opponent casts a spell with the chosen mana value, you draw a card and create a Treasure token.

Adorned — Mercenary Lancer gets +2/+2 as long as it's equipped and/or enchanted.

Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Flying, vigilance

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

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.

Embellish {4}{W} (If you cast this spell for {4}{W}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
When Meticulous Mechanist enters, scry 1.