msem-instigator

Colorless creatures you control get +1/+1.

Return target nonland permanent to its owner's hand.
Inscribed creature gets +1/+1 and has flying.
Inscribe {3}{U} ({3}{U}: 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.)

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Shrouded Cackler can't block.

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.)

{T}, Pay 1 life: Add one mana of any color. Spend this mana only to cast an instant or sorcery spell.

This spell costs {2} less to cast for each face-down creature you control.
Flying

Vigilance
Shuye, Forever Watching's power and toughness are each equal to the number of noncreature permanents you don't control.

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

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.)

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.

{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}.

{T}: Add {W} or {B}.
{T}, Sacrifice Sigil of Martyrdom: Add {W}{B}.

{T}: Add {R} or {G}.
{T}, Sacrifice Sigil of Savagery: Add {R}{G}.

{T}: Add {G} or {W}.
{T}, Sacrifice Sigil of Unity: Add {G}{W}.

Target player draws two cards and loses 2 life.

Create a 1/1 white Soldier creature token. Then put a +1/+1 counter on a creature you control.

Counter target spell unless its controller pays {1} and 3 life.

Mill three cards, then counter target spell unless its controller pays {X}, where X is the greatest mana value among cards milled this way.