msem-instigator

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Each opponent sacrifices an artifact or enchantment.
Showcase {2}{G}{G} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

[+1]: Remove up to one loyalty counter from each other planeswalker. Up to one target player loses 1 life for each counter removed this way.
[–1]: For each other player and permanent, remove a counter from it or give it another counter of a kind that permanent or player already has.
[–4]: Put target nonland permanent on the bottom of its owner's library.

All creatures able to block Raiun Bay Merchant do so.

Creatures you control get +2/+2 and gain trample until end of turn. If you cast this spell from exile, creatures you control get an additional +2/+2 until end of turn.
Prophecy {2}{G}{G} (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.)

{2}{R}, Sacrifice an artifact or creature: It deals 2 damage to any target.

Menace
Servitor Vanguard gets +X/+X, where X is the number of other artifacts you control.

When Manglehorn Hunter enters, draw a card and you lose 1 life.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Worried Vulpine has three or more +1/+1 counters on it, remove them all and transform it.

Exile target nonland permanent you control, then return that card to the battlefield under its owner's control. When it enters the battlefield as a creature, it deals damage equal to its power to target creature or planeswalker an opponent controls.

When Conjured Shade dies, target creature you don't control gets -1/-1 until end of turn.

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Noncreature spells you cast cost {X} less to cast, where X is All-Encompassing Akvan's power.

{1}, Sacrifice Gasoline Canister: It deals 1 damage to any target. If a creature or planeswalker dealt damage this way would die this turn, exile it instead.

Parasitic Bloodsucker gets +1/+1 as long as you control a Swamp.
{2}{B}: Parasitic Bloodsucker gains lifelink until end of turn

Flying
When Boundless Hopes enters, another target creature you control gains flying until end of turn.
Fleeting {U} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

When Bal's Descent enters, each player sacrifices a creature, discards two cards, and mills three cards.
{1}{B}{B}: Transform Bal's Descent. Activate only if your fealty to Swamps is five or greater.

Whenever an attacking creature dies, you may pay {R}. If you do, create a 2/1 red Merfolk creature token.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Weedy Whackers attacks, create a 1/1 green Insect creature token that's tapped and attacking.

Flying
Whenever Crane Legionnaire attacks, tap target creature defending player controls.

Flying, trample
When this creature transforms into Griselbrand, the Usurper, draw seven cards.

Vigilance
When Traveling Duo enters, create a 1/1 colorless Servo artifact creature token.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, put the top card of your main library on the bottom of the archived library.
{U}: Exchange a card from the archived library with a card from your hand.

Whenever an opponent casts a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Spells your opponents cast cost an additional 2 life to cast until your next turn.

Destroy target planeswalker. Mummy's Grin deals 2 damage to that planeswalker's controller.