msem-instigator

Mill five cards, then you may exile any number of cards from your graveyard. Create an X/X black Horror creature token with menace, where X is the number of cards exiled in this way. (To mill five cards, put five cards from the top of your library into your graveyard.)

Return up to one target creature you control and up to one target creature you don't control to their owners' hands.

Equipped creature gets +2/+0. As long as it's a Knight, it has first strike.
Equip {1}{W}

Defender (This creature can't attack.)
Whenever you cast a spell, if it isn't your main phase, Serene Meditant loses defender until the beginning of your next end step.

Flash
Menagerie — When Seven Seas Scourge enters, if there are five or more creature types among creatures you control, counter target spell with mana value 4 or less.

{2}: Equipped creature phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
Equipped creature can't be blocked except by Rogues and is a Rogue in addition to its other types.
Equip {1}

When Shaman of Burning Ashes enters, return target instant or sorcery card from your graveyard to your hand. When you do, each opponent loses X life, where X is that card's mana value.

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

Whenever Shifty Fink attacks, if you have more cards in hand than defending player, it gets +2/+1 until end of turn.

Kicker—Return a creature you control to its owner's hand. (You may return a creature you control to its owner's hand in addition to any other costs as you cast this spell.)
Counter target spell. If Shinrei's Ruse was kicked, draw a card.

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

Search your library for two basic land cards, reveal them, put them into your hand, then shuffle. (Then exile this card. You may cast the creature later from exile.)

{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.

Flash
Harmony — Another target creature gets +1/+0 and gains indestructible until end of turn.
When Siamang Tale-Singer enters, harmonize. (Trigger up to one harmony of a permanent you control.)

Flash
Flying
Menagerie — Whenever Sigilwing Familiar deals combat damage to a player, if there are five or more creature types among creatures you control, draw a card.

When Sihari's Groundblazer enters, create a red Aura enchantment token named Searing Crags attached to target land. The token has enchant land, “Enchanted land's name is Charred Causeway” and “Enchanted land has {T}: This land deals 1 damage to each opponent.”

You may look at the top card of your library any time, and you may play Deserts from the top of your library.
[+1]: You gain 1 life. You may discard a card. If you do, draw a card.
[–2]: Sihari deals 2 damage to any target. You may play an additional land this turn.
[–4]: Create an X/X red and green Sand Elemental creature token with trample and haste, where X is the number of lands you control.

Silent Ridge enters tapped.
{T}: Add {B}.
Desertcycling {1}{B} ({1}{B}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

{T}: Untap another target nonland permanent. Activate only as a sorcery.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you cast your first spell outside your main phase each turn, add a quest counter.
Draw cards equal to the number of quest counters on Siltbottom Expedition, then discard that many cards.
Put up to two target instant or sorcery cards from your graveyard on top of your library in any order, then draw a card.

Whenever Siltbottom Freebooters attacks, target Pirate gains menace until end of turn.

{2}{U}, {T}: Look at the top card of your library. If it's a Scout card or a card with an Adventure, you may reveal it and draw a card.

Whenever you discard one or more cards, create a Treasure token and draw a card. This ability triggers only once each turn.
Whenever two or more creatures you control attack, you may discard a card. If you do, target creature can't block this turn.

When Silverhorn Battlemaster enters, put a +1/+1 counter on up to two target Warriors you control.
Whenever Silverhorn Battlemaster deals combat damage to a player, permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

This spell costs {1} less to cast for each poison counter your opponents have.
Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)
At the beginning of your end step, each opponent with seven or more poison counters loses the game.