msem-instigator

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control becomes renowned, you may have it fight target creature you don't control. (Each deals damage equal to its power to the other.)

At the beginning of combat on your turn, if you control six or more lands, put a +1/+1 counter on target creature you control.

As Sturdy Outpost enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {G}, {W}, or {U}.

Concord — At the beginning of combat on your turn, if there are four or more card types among permanents you control, Sturdyshell Hammerclaw gets +2/+1 and gains trample until end of turn.

Flying
{B}, Sacrifice another creature: Draw a card.

When Stygian Leviathan enters, target opponent loses life equal to the number of Curses attached to them and you gain that much life.

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Destroy target artifact or enchantment. You gain 2 life.

Exile up to three target cards from a single graveyard.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Target player draws a card. Put target spell or nonland permanent that player controls on top of its owner's library.

First strike, vigilance
When Subnautical Legionnaire enters, choose artifact, enchantment, or Merfolk. Exile target nonland permanent you don't control until you control no permanents of the chosen type.

Gain control of target noncreature permanent.
Coalesce {8}{U}{U} (You may cast this from your graveyard for {8}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Enchant opponent
Whenever Substack Exploit or another Curse becomes attached to enchanted player, that player loses 1 life and you gain 1 life.

Substack Ports enters tapped.
{T}: Add {U} or {B}.
{U}{B}, {T}, Sacrifice Substack Ports: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Whenever you create a token, Substack Runner gets +1/+0 and can't be blocked until end of turn.

Once each turn, when you discard a card, you may draw a card.
{1}, Discard a card: Substack Smuggler can't be blocked until end of turn.

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.)
At the beginning of your end step, Substack Sniper deals 1 damage to you and to each cursed opponent.

This spell costs {1} less to cast and has flash as long as there are four or more card types among cards in your graveyard.
Draw two cards.

Lifelink

Flying
Whenever a creature dealt damage by Subturgian Legionnaire this turn dies, create a 1/1 black Vampire creature token with lifelink.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
At the beginning of your upkeep, if Subturgian Proliferator engorged a creature card, you may pay {3}{B}. If you do, create a black Zombie creature token with power equal to the engorged card's power and toughness equal to that card's toughness.

When Suburban Farmer enters, you may search your library for a basic Plains card, reveal it, put it into your hand, then shuffle.
When Suburban Farmer dies, you gain 3 life.

When Suburban Runebrawler enters, exile target instant or sorcery card with mana value 2 or less from your graveyard.
Landfall — Once each turn, when a land you control enters, you may cast a copy of the exiled card without paying its mana cost.

Subway Shambler can't be blocked by creatures with lesser power.
At the beginning of each end step, if you're horrific, put a +1/+1 counter on Subway Shambler. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Destroy target untapped creature.