msem-instigator

Prowess
Each instant and sorcery card with mana value 3 or less in your hand has inscribe. The inscribe cost is equal to its mana cost increased by {1}{U/R}. (Pay that card's mana cost increased by {1}{U/R}: Exile that card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

When Shaidostan Cryoforger enters, exile the top card of your library.
When Shaidostan Cryoforger dies, you may put the exiled card into your hand.

As long as Shambling Morass is on the battlefield or in your graveyard, it's a land in addition to its other types.
When Shambling Morass dies, you may pay {1}. If you do, you draw a card and you lose 1 life.

You may play Shanty Town from your graveyard as long as seven or more cards are in your graveyard.
Shanty Town enters tapped.
{T}: Add {W} or {B}.
Cycling {1}{W}{B} ({1}{W}{B}, Discard this card: Draw a card.)

Create a colorless Equipment artifact token with “Equipped creature gets +1/+1” and equip {1}. You may attach it to a creature you control.
Inscribe {3}{R} ({3}{R}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

As Shardstone Rift enters, you may pay 2 life. If you don't, Shardstone Rift enters tapped.
{T}, Sacrifice Shardstone Rift: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)

Discard a card, then draw a card.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Create a 1/1 colorless Human creature token. Put your choice of a flying, vigilance, prowess, or hexproof counter on it. If you control a permanent with mana value 5 or greater, instead put any number of those counters and a +1/+1 counter on it.

As long as it's your turn, Shell Merc has first strike and prowess.

Concord — {T}: Tap target nonland permanent. Activate only if there are four or more card types among permanents you control.

Sheltered Haven enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}, {T}, Sacrifice Sheltered Haven: Draw a card.

{T}: Add {C}.
As long as Shengin Heartland is in your graveyard, lands you control have “{T}: Add {G} or {U}.”

You may look at the top card of your library any time.
{T}: Target player mills a card.

Shepherd of the People can't be blocked by creatures with power 2 or less.
Whenever another Citizen or Peasant you control enters, Shepherd of the People gets +1/+1 until end of turn.

Art of war — At the beginning of your end step, if Sheraku Elite dealt damage to an opponent this turn, put a +1/+1 counter on it.

Target player discards a card.
Monument {1}{B} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

{T}: Add {C}.
{1}, {T}, Sacrifice Shifting City: Search your library for a basic land or Satrapy card, put it onto the battlefield tapped, then shuffle.

{T}: Add {C}.
{2}, {T}, Sacrifice Shifting Frontiers: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

({T}: Add {G} or {U}.)
Whenever Shifting Glade becomes tapped, you lose 1 life unless you control two or more basic lands.

Flying
When Shiftscale Drake enters, look at the top card of your library. You may put that card into your graveyard.

{T}: Add {C}.
{T}, Sacrifice Shiftscape Canyon: Choose a basic land type other than Plains. Create a colorless land token that's a Plains and the chosen basic land type. Activate only during your upkeep.

{T}: Add {C}.
{T}, Sacrifice Shiftscape Cascade: Choose a basic land type other than Island. Create a colorless land token that's an Island and the chosen basic land type. Activate only during your upkeep.

{T}: Add {C}.
{T}, Sacrifice Shiftscape Crag: Choose a basic land type other than Mountain. Create a colorless land token that's a Mountain and the chosen basic land type. Activate only during your upkeep.

{T}: Add {C}.
{T}, Sacrifice Shiftscape Grove: Choose a basic land type other than Forest. Create a colorless land token that's a Forest and the chosen basic land type. Activate only during your upkeep.