msem-instigator

Whenever a nonbasic nontoken land enters under an opponent's control, create a tapped colorless land token named Fading Rift with “{T}, Sacrifice this land: Add one mana of any color.”

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.

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.

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.

When Meteor Harbinger enters, choose one —
• Meteor Harbinger deals 2 damage to each creature.
• Each player sacrifices two lands.
• Meteor Harbinger deals 2 damage to each of two target players or planeswalkers.

Flash
Wanderlust — When Microzoologist enters, search your library for a creature card with mana value 1. If you control four or more differently named lands, you may search for a creature card with mana value 3 or less instead. Reveal that card, put it into your hand, then shuffle.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a +1/+1 counter on Mirrorcast Battlemage.
Remove three +1/+1 counters from Mirrorcast Battlemage: Copy target instant or sorcery spell you control. You may choose new targets for the copy. Activate only once each turn.

({T}: Add {B} or {R}.)
Molten Falls enters tapped.
{1}, {T}: Add {B}{B} or {R}{R}.

When Monstrous Hunter enters, destroy up to one target creature.
At the beginning of each end step, if a creature died this turn, you draw a card and you lose 1 life.

{T}: Add {C}.
{4}: Put a +1/+1 counter on Monument of Queens. You may have it become a 0/0 Avatar creature with flying, first strike, vigilance, trample, and lifelink until end of turn. It's still a land.

Lifelink
Whenever Morning's Warden becomes the target of a spell or ability an opponent controls, exile target creature that player controls.

{T}: Add {C}.
{1}, {T}, Sacrifice Morphic Verge: Choose two different basic land types. Create a colorless land token that's the chosen types.

You may have Mutalithic Golem enter as a copy of any land on the battlefield, except it's an artifact in addition to its other types.

As Nebula of Empty Gold enters, choose two or three colors. You lose life equal to the number of colors chosen this way.
{T}: Add one mana of any of the chosen colors.

{T}: Add {C}.
Wanderlust — {6}, {T}: Draw two cards. Activate only if you control four or more differently named lands.

At the beginning of combat on your turn, you may attach target Equipment you control to Nina, Master of Arms.
Whenever Nina attacks, the next artifact spell you cast this turn costs {R/W}{R/W} less to cast. (This can reduce the amount of generic mana you pay.)

Flash
When Notorious Smuggler enters, target opponent reveals their hand. Choose a nonland card revealed this way. Copy it. You may cast the copy this turn. (You still pay its costs, including color. Copies of permanents enter as tokens.)

Flying
Whenever Novaheart Dragon enters or attacks, you may take an extra turn after this one. If you do, you lose the game at the beginning of that turn's end step.

Flash
Whenever you cast an artifact or enchantment spell, put a +1/+1 counter on Observer of Secret Paths. It can't be blocked this turn.

{T}: You may put a land card from your hand onto the battlefield.
{1}, {T}: Aetherize target land you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Oldgrove Nurturer enters with a +1/+1 counter on it.
{G}, Remove a +1/+1 counter from a creature you control: Create a 1/1 colorless Construct artifact creature token.

Whenever you cast a noncreature spell, Omegalomania deals 2 damage to any target. Whenever a permanent you don't control dealt damage this way dies this turn, return it to the battlefield tapped under your control.

Exile two target permanents you control, then return them to the battlefield under your control.

When Opulent Proprietor enters, you may search your library and/or graveyard for an Aura, Aurashaper, Equipment, or Vehicle card, reveal it, and put it into your hand. If you search your library this way, shuffle.

{T}: Look at the top card of your library. If it's a land card, you may reveal it and put it into your hand.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)