msem-instigator

Whenever a player casts a creature spell, they sacrifice a creature.
Revive—{3}{B}{G}, Sacrifice a creature. ({3}{B}{G}, Sacrifice a creature, 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.)

Other creatures you control get +0/+1.
Whenever a creature you control perseveres, you gain 1 life. (A creature perseveres when it survives damage.)

Tap a creature you control: Prevent the next 2 damage that would be dealt by target creature this turn.
Tap a Reflection creature you control: Prevent all damage that would be dealt this turn by a source of your choice.

You may tap or untap target permanent.
Draw a card.

When Shifty Squirrel enters the battlefield, you gain 3 life.
Sacrifice a creature: Transform Shifty Squirrel.

Enchant creature
Enchanted creature has lifelink and protection from its colors. This effect doesn't remove Shimmerhold. (This permanent can't be targeted, dealt damage, enchanted, or equipped by anything its color.)

Flying, haste
Whenever Shimmering Dragon attacks, for each creature you control, create a tapped and attacking token that's a copy of that creature. Exile the tokens at the beginning of the end step.

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}

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

Whenever Shoreline Stormers deals damage to a player, draw a card.
{2}{U}: Target creature can't be blocked this turn.

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

Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)
When Shoring Naiad enters the battlefield, if {U} was spent to cast it, you may return an instant or sorcery card from your graveyard to your hand.

Prevent all combat damage that would be dealt this turn. You get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

Whenever equipped creature deals damage to a creature, that creature gets -2/-2 until end of turn.
Equip {2}

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter the battlefield tapped.

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

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.)

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

Enchant creature
Enchanted creature gets +1/+1 and has hexproof.

As long as you are glorious, you may look at the top card of your library. (You are glorious as long as you have a glory counter.)

At the beginning of each end step, if you gained life this turn, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

At the beginning of each upkeep, choose one or more —
• Untap target artifact.
• Untap target creature.
• Untap target land.

Whenever Skitterthorns blocks or becomes blocked, creatures you control gain deathtouch until end of turn.

Skulking Claw can't be blocked by creatures with greater power.
Skulking Claw gets +1/+0 for each unblocked attacking creature you control.

Creatures with power less than Skull-Crowned Chief's power can't block.