msem-instigator

Whenever a creature card is put into your graveyard from anywhere, it gains revive until the beginning of your next end step. The revive cost is equal to its mana cost increased by {1}. (Pay that card's mana cost increased by {1}, Exile that card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

First strike
When Gavis's Dragoons enters, exile another target creature until Gavis's Dragoons leaves the battlefield.
Spells with the same name as the exiled card can't be cast (as long as this creature is on the battlefield).

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Tap up to two target creatures [with the same name]. Those creatures don't untap during their controller's next untap step.

Menace

Flying
When Sahra's Harbinger enters, reveal the top six cards of an opponent's library and separate them into two piles. That opponent chooses one of those piles and puts it into their hand. You may cast any number of nonland cards in the other pile without paying their mana costs.

Cosmic Coalescing deals X damage to any target. You may reveal a noncreature card with mana value X or less you own from outside the game and put it into your hand. X can't be 0.
Exile Cosmic Coalescing.

Exchange control of all creatures you and target player control until end of turn. Untap those creatures. They gain haste until end of turn.

Forsaken Sunseeker gets +1/+1 and has flying as long as it's not your turn.

[+2]: You may sacrifice a permanent or discard a card. If you do, draw a card.
[–X]: Return target creature card with mana value X or less from your graveyard to the battlefield.
[–8]: You get an emblem with “Whenever a permanent you control dies, return a permanent card with lesser mana value from your graveyard to the battlefield.”

Menace
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

{2}{R}, {T}, Exert Hinterland Ritualist, Sacrifice another creature: Hinterland Ritualist deals damage equal to the sacrificed creature's power to any target. Activate only as a sorcery. (An exerted creature won't untap during your next untap step.)

Syurrai Traitor gets +1/+1 as long as you control a Plains.
{3}{W}: Create a 1/1 white Soldier creature token.

Choose one —
• Create two 1/1 black Worm creature tokens.
• Put up to two target cards from your graveyard on top or bottom of your library.

When Whisper Witch enters, choose up to one target creature. That creature's controller mills four cards, then puts that creature on top of their library.

Haste
Arise {2}{R} ({2}{R}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Whenever Field Chaplain perseveres, you gain 3 life. (A creature perseveres when it survives damage.)

Whenever Single-Minded Mob becomes untapped, it gets +2/+2 until end of turn.

When Shackled Memories enters, return target instant or sorcery card from your graveyard or card with flashback you own from exile to your hand.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, create a 1/1 white Spirit creature token with flying.

Whenever a creature in Heaven's Fire Ascetic's pack attacks, that creature deals 1 damage to defending player. (Two or more creatures you control with equal power are in a pack.)

As an additional cost to cast this spell, sacrifice a permanent.
Reveal the top card of each of your libraries. Put each permanent card revealed this way with mana value less than or equal to the sacrificed permanent's onto the battlefield.

Menace (This creature can't be blocked except by two or more creatures.)

Hexproof
When Overburdened Trader enters, create three 1/1 colorless Construct artifact creature tokens.

When Suburban Runebrawler enters, exile target instant or sorcery card with mana value 2 or less from your graveyard.
Landfall — Once each turn, when a land you control enters, you may cast a copy of the exiled card without paying its mana cost.

When R-12 Lone Digger enters, it deals 3 damage to target player or planeswalker.

First strike, menace, lifelink
{X}{2}{B}, Discard Wihtfyr: Create a tapped 0/0 Skeleton Army creature token with “This creature gets +1/+1 for each creature card in your graveyard.” For each of up to X Armies, put your choice of a first strike, lifelink, or menace counter on that Army.