msem-instigator

Prevent all combat damage that would be dealt to Silent Reaver.
Prevent all combat damage Silent Reaver would deal to creatures.

Flash
You may cast cryptic spells as though they had flash. (Artifacts, enchantments, and modal spells are cryptic.)

Reach

{2}, Pay 2 life: Silkwrap Brawler gains indestructible until end of turn.

Whenever Silt Lurker deals combat damage to a player, mill three cards, then draw a card if seven or more cards are in your graveyard.
Cycling {G} ({G}, Discard this card: Draw a card.)

Concord — Silt-Trench Brute gets +3/+3 and has trample as long as there are four or more card types among permanents you control.

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.

Silver-Dawn Elder gets +2/+2 as long as you control five or more lands.
Revive—{2}{G}{G}, Discard a card. ({2}{G}{G}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Menace
Whenever Silver-Dawn Radiant becomes the target of a spell or ability you don't control, it deals damage equal to its power to that spell or ability's controller.

When Silvercrest Historian enters, scry 1, then investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Trample
Whenever Simian Sentinel attacks, it gets +X/+0 until end of turn, where X is the number of lore counters on Sagas you control.

First strike

Whenever Simian Striker attacks, it gets +3/+0 until end of turn.

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.

Death knell — You gain 2 life. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Flying
Sire of Empires gets +1/+1 as long as you control another creature, has lifelink as long as you control an enchantment, and has vigilance as long as you control an artifact.

Haste
Sixpod Sprinter can't be blocked except by creatures with flying or reach.

Flying, trample
Whenever Skali, the Last Sunfeather attacks, abound. If a creature spell is cast this way, you may have that creature enter tapped and attacking. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)

When Skeletal Shredwing enters, target creature can't block this turn.
Revive {5}{R} ({5}{R}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Whenever an embattled creature you control dies, you may return Skhorvall Eternal from your graveyard to your hand. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Flying
Whenever Skhorvall Patrol deals combat damage to a player, look at the top card of that player's library.

When Skhorvall Raider enters, if you control an embattled creature, Skhorvall Raider deals 2 damage to any target. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Menace
Whenever Skhorvall Warleader attacks, it gets +1/+0 until end of turn for each other attacking Warrior you control.

Whenever a player casts an instant or sorcery spell from their hand, you may exile that card as it resolves instead of putting it anywhere else.
Whenever Skill Sketcher attacks, you may cast a card exiled with it. That spell costs {X} less to cast, where X is Skill Sketcher's power.

Flying
Spells you cast from anywhere other than your hand cost {2} less to cast.
Spells your opponents cast from anywhere other than their hand cost {2} more to cast.