msem-instigator

Whenever equipped creature attacks, put a charge counter on Shimmersting, then create a token that's a copy of equipped creature and that's tapped and attacking for each charge counter on Shimmersting, except the tokens aren't legendary. Exile the tokens at the beginning of the end step.
Equip {5}

Whenever Shina Taiyohata or another creature you control enters, you may have that creature gain haste. If you do, return that creature from the battlefield to its owner's hand at the beginning of the next end step.

[+2]: Exile any number of target artifacts and/or enchantments you control, then return them to the battlefield under your control. You may draw that many cards.
[–4]: Search your library for an enchantment card, put that card onto the battlefield, then shuffle.
[–12]: Put any number of permanent cards you own from outside the game onto the battlefield tapped.

Shining Crusader has protection from all colors as long as you control no colored permanents.

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Sacrifice a creature: Shinrei of the Ghosting Way can't be blocked this turn.
Whenever one or more Rogues you control deal combat damage to a player, return a creature card from your graveyard to your hand.

Flying, lifelink
Whenever Shioki, Imperial Heir attacks, exile any number of other target nonland permanents you control, then return those cards to the battlefield under their owner's control.

Equipped creature gets +2/+2 and has flying and lifelink.
When equipped creature deals combat damage to a player, unattach Shionoshio, Ocean's Vow, then transform it.
Equip {W}{U}
Shionoshio can be your commander.

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

{8}{U}{U}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
When Shipway Whale becomes monstrous, target player exiles all cards in their library, then shuffles their graveyard into their library.

When Shizen, the Thousand Steps enters, draw a card, then choose a creature card name.
Creatures you control with the chosen name get +0/+1 and have hexproof.

Partner with Kasoha, Keeper of Truths (When this creature enters, target player may put Kasoha into their hand from their library, then shuffle.)
Whenever Shizura, Keeper of Traditions or another legendary creature dies, target player draws two cards and loses 2 life.

Flying
Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast your second spell each turn, draw a card.

When Shojiro, the Wavewaker enters, submerge up to eight target creatures your opponents control. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Flying
When Shomi's Savior enters, scry 3, then you gain 3 life.
Whenever you scry, put a +1/+1 counter on Shomi's Savior.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Marked creatures your opponents control lose all abilities.

Reveal the top four cards of your library. You may put a permanent card revealed this way with mana value less than the greatest mana value among permanents you control onto the battlefield. Put the rest on the bottom of your library in a random order.

Target creature you control deals damage equal to its power to target creature you don't control. For each point of excess damage dealt this way, put a +1/+1 counter on the creature you control.

Haste
Each creature with toughness greater than its power can't block.

Whenever you create an Idol token, put a +1/+1 counter on Shrine of Elder Lords.
{T}: Add {C}.
{3}: Put a +1/+1 counter on Shrine of Elder Lords, then you may have it become a 0/0 Elemental creature with vigilance until end of turn. It's still a land.

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if you've cast a noncreature spell this turn.

{T}: Add {C}.
Shrine of the World-Shepherd's power and toughness are each equal to the number of differently named lands you control.
{3}{G}: Shrine of the World-Shepherd becomes a Beast creature in addition to its other types until end of turn.

{T}: Add {C}.
{T}: Choose a color. Add one mana of that color unless you control a permanent of that color. Spend this mana only to cast a permanent spell.

If a spell or ability would cause a player to discard one or more cards, that player discards that many cards at random instead.
Whenever a player discards a card, that player loses 2 life.

Return up to one target creature to its owner's hand. If you do, that player discards a card at random.
Coalesce {5}{U}{B} (You may cast this from your graveyard for {5}{U}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Shroud the World in Doom deals combat damage to an opponent, that player discards a card at random.

Frozen Hinterlands enters tapped.
{T}: Add {W} or {B}.
{1}{W}{B}: Until end of turn, Shrouded Rooftops becomes a 3/3 white and black Illusion creature with with lifelink and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)