msem-instigator

When Siamang Minstrel enters, you may put a lore counter on target Saga you control.

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.)

At the beginning of your upkeep, you lose life equal to the number of Armies you control, then recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Vigilance
Whenever Sibling of All Elements attacks, it gains flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, deathtouch, indestructible, lifelink, menace, and trample.

Enchant creature
Enchanted creature gets +1/+0 and has deathtouch.
When Sickening Madness is put into a graveyard from the battlefield, draw a card.

Siege Ent can't be blocked by creatures with power 2 or less as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Gain control of target nonland permanent an opponent controls. Its owner reveals cards from the top of their library until they reveal a card that shares a type with that permanent, then puts it onto the battlefield and shuffles.

Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
When Siegebreaker Ogre enters, create two 1/1 red Goblin creature tokens with haste.

Deathtouch
When Siesa Tremund enters, for each player, search that player's library for a card and exile it. That player shuffles. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any type to cast those spells.

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U} (You may cast this from the battlefield for its wander cost.)

Draw three cards, then discard a card unless you've catalyzed three or more times this turn.

When Sift Through False Leads enters, exile the top five cards of your library, then investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{2}, Sacrifice a Clue: Put a card exiled with Sift Through False Leads into your hand.

First strike
Whenever Sighted-Caste Knight deals combat damage to a player, draw a card.

Revive {3}{B} ({3}{B}, 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.)

When Sights Beyond enters, scry 3.
Concord — At the beginning of your upkeep, if there are four or more card types among permanents you control, draw a card.

Prowess
{T}: Catalyze, then catalyze again. Activate only if Sigil Slinger's power is 5 or greater. (The next spell you cast this turn costs {2} less to cast.)

{T}: Add {R} or {W}.
{T}, Sacrifice Sigil of Brutality: Add {R}{W}.

{T}: Add {G} or {U}.
{T}, Sacrifice Sigil of Creation: Add {G}{U}.

{T}: Add {B} or {R}.
{T}, Sacrifice Sigil of Destruction: Add {B}{R}.

{T}: Add {W} or {U}.
{T}, Sacrifice Sigil of Duty: Add {W}{U}.

Whenever target creature deals combat damage to a player this turn, create a token that's a copy of it.

Untap target creature. It gets +2/+2 until end of turn.
Cycling {W} ({W}, Discard this card: Draw a card.)

{T}: Add {B} or {G}.
{T}, Sacrifice Sigil of Growth: Add {B}{G}.

{T}: Add {U} or {R}.
{T}, Sacrifice Sigil of Ingenuity: Add {U}{R}.

{T}: Add {U} or {B}.
{T}, Sacrifice Sigil of Malice: Add {U}{B}.