msem-instigator

Destroy target creature with flying. (Then exile this card. You may cast the creature later from exile.)

Tap up to two target permanents. They don't untap during their controller's next untap step. You may put Snooze into its owner's library third from the top.

Snow Drift 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 {U}.
{4}{U}: Snow Drift becomes an Elemental creature. (This effect lasts indefinitely.)

Enchant artifact or creature
Enchanted permanent doesn't untap during its controller's untap step.
Whenever you make first contact, scry 1. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Snowy Misthorn can block creatures with distorted as though it was tapped.

If you control seven or more creatures, you may cast Sociable Giant without paying its mana cost.
Trample

Target player mills six cards. Return each creature that shares a name with a card milled this way to its owner's hand.
Prophecy {1}{U} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Flying

Whenever you make first contact, return target creature card from your graveyard to the battlefield. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Tap all lands target player controls and that player loses all unspent mana.

When Something in the Woods enters or at the beginning of your upkeep, Something in the Woods explores. If it explores a creature card, you may have it become a copy of that card. (It loses this ability. To explore, 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.)

Enchant creature
Enchanted creature gets +1/+1 for each creature you control.

As Sorcerous Spyglass enters, look at an opponent's hand, then choose any card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

When Sorrowslayer enters, put a +1/+1 counter on target creature.
Remove a +1/+1 counter from Sorrowslayer: Trigger a death knell of a permanent you control. Activate only once each turn and only as a sorcery.

{1}, {T}: Exile target card from a graveyard. Scry 1.
{T}, Exile Soul Gate: Exile all graveyards.

Whenever you sacrifice a permanent, you may put a soul counter on Soul's Guidestone.
As long as there are five or more soul counters on Soul's Guidestone, it's a 6/6 Golem artifact creature with menace and vigilance.

Advance {2}{R} (Cast this for {2}{R} to advance it as it enters. {2}{R}: Advance this as a sorcery.)
Haste
Whenever Soulblade Warrior advances, it gets +2/+0 until end of turn.

Other Spirits you control get +1/+1.
As long as a Spirit you control has flying, Soulcleaver has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

First strike, haste
Whenever Soulflare Nymph deals damage to a creature, exile that creature.

Flash
Other Rogues you control get +1/+1.
Rogue spells you cast have flash.

If target creature would leave the battlefield this turn, return it to its owner's hand instead.
Fuse (You may cast one or both halves of this card from your hand.)

Exile the top card of your library. You may have Spark Inspiration deal 2 damage to each opponent. If you don't, you may play that card until end of turn.

{T}: Add {C}.
{T}: Add one mana of any color among planeswalkers you control.
{1}, {T}: Put a loyalty counter on target planeswalker that activated a loyalty ability this turn.

Primal {2}{R} (During your turn, you may cast this spell for {2}{R} instead of playing a land.)
Target creature gets +2/+0 and gains double strike until end of turn.