msem-instigator

{1}{U}: Return Sparkling Jackalope and target creature to their owner's hands.
{5}{U}{U}: Sparkling Jackalope gets +4/+4 and gains flying until end of turn.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Spectral Hunter envisions a creature card, creatures you control get +1/+0 until end of turn.

Prowess
Whenever you cast a noncreature spell, you may pay {R}. If you do, post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

Hexproof
Whenever an opponent casts a noncreature spell, put a +1/+1 counter on Spellbane Vulpine.

This spell costs {1} less to cast for each other spell you've cast this turn.

Haste
Whenever Spellslinger Elf deals combat damage to a player, draw a card, then you may cast a card from your hand with mana value 3 or less without paying its mana cost.

Spellwoven Monster can't be the target of spells or abilities in any zone.
As you cast an instant or sorcery spell, reveal cards from the bottom of your library until you reveal an instant or sorcery card. You may add that card's effects to that spell. Then shuffle.

When Spiked Burrower dies, if it didn't have a counter on it, return it to the battlefield under your control with a +1/+1 counter or a lifelink counter on it.

Trample
When Spikehorn Behemoth leaves the battlefield or phases out, draw a card.

Once each turn, when one or more cards are put into an opponent's graveyard from their library, you may draw a card.

Spiny Ridge enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {R}.
{4}{R}: Spiny Ridge becomes a Lizard creature. (This effect lasts indefinitely.)

Spired Canopy enters tapped unless another player controls a land that could produce {G} or {U}.
{T}: Add {G} or {U}.

Enchant creature
Enchanted creature gets +2/+2 and has vigilance.
Sacrifice Spirit Guidance: Exile enchanted creature, then return it to the battlefield under its owner's control.

Whenever Spirit of Infamy attacks, post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)
Spirit of Infamy gets +2/+0 for each bounty counter on it.

When Spirit of the Falls enters, choose a permanent type. Return all other permanents of the chosen type to their owner's hands.
Discard two land cards: Spirit of the Falls gains hexproof until end of turn.

When Spiritual Colpah dies, you may return target creature card from your graveyard to your hand.

Exile target artifact, creature, or enchantment. Return that card to the battlefield under its owner's control at the beginning of the next end step.
Draw a card.

Target creature gets +2/+2 and gains lifelink until end of turn. Whenever that creature perseveres this turn, target opponent loses 2 life. (A creature perseveres when it survives damage.)

Whenever a nontoken creature you control perseveres, create a 1/1 blue Nymph creature token with flying. (A creature perseveres when it survives damage.)

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)

Flying
Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)

Whenever Sporecaster or another Insect you control enters, each opponent loses 1 life.

When Sporecrowned Scavenger enters, target opponent loses life equal to the number of Insects you control and you gain that much life.

Haste
Whenever Spotted Slugger deals combat damage to a player, you may have it deal damage equal to its power to target creature.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)