msem-instigator

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you cast an Equipment or Adventure spell, add a quest counter.
1, 2 — Exile the top two cards of your library, then choose one of them. You may play that card until the end of your next turn.
3 — Until end of turn, target creature you control gets +1/+0 and gains double strike, vigilance, and indestructible.

Energize deals 3 damage to any target.
Catalyze. (The next spell you cast this turn costs {1} less to cast.)

Flying, vigilance
Orzhov Benefactor can't attack or block unless you pay {1} for each debt counter on it.
At the beginning of your upkeep, put a debt counter on Orzhov Benefactor.
{2}: Remove a debt counter from Orzhov Benefactor.

Create a 2/2 black Zombie creature token, then sacrifice a creature.

Equipped creature gets +2/+2 and has vigilance.
Equip {4}
Wanderlust — Wayfarer's Adornments has equip {0} as long as you control four or more differently named lands.

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Griffin Skycaller enters, target creature you control gets +1/+1 and gains flying until end of turn.

Equipped creature gets +1/+1 and has vigilance and lifelink.
Equip {3}

Kalib Kabir has hexproof as long as it has no +1/+1 counters on it.
Kalib Kabir has trample as long as it has a +1/+1 counter on it.
{G}: If Kalib Kabir has a +1/+1 counter on it, remove all +1/+1 counters from it. Otherwise, put a +1/+1 counter on it. Activate only once each turn and only during your turn.

As Prairie Monastery enters, you may tap an untapped creature you control. If you don't, Prairie Monastery enters tapped.
{T}: Add {G} or {W}.

When Osseous Augur enters, target creature an opponent controls gets -1/-1 until end of turn. If that creature's controller is cursed, that creature gets -3/-3 until end of turn instead.

Destroy target untapped creature.

{G}, {T}: Target creature with power 4 or greater fights any number of target creatures you control.

Flying, trample
Whenever Raidragos' Avenger deals combat damage to a player, create a 5/5 red Dragon creature token with flying.
Creatures you control get +1/+0 for each Dragon you control.

When Felhide Marauder enters, if you control a creature with power greater than its base power, Felhide Marauder gains haste until end of turn.

Choose one—
• Manifest target creature card from your graveyard. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
• Return up to two target creature cards from your graveyard to your hand.

{1}, {T}, Move a -1/-1 counter from another creature onto Harried Apothecary: Each opponent loses 1 life and you gain that much life.

Move all counters from target creature onto another target creature.

Flying, deathtouch
Whenever Queen of the Hive deals combat damage to a player, create a 1/1 green Insect creature token for each Insect you control.

Inspired — Whenever Emperor Dan Te Mogui becomes untapped, look at the top three cards of your library. Put one into your graveyard, one on the bottom of your library, and one on top.
When Emperor Dan Te Mogui dies, you may put it on the bottom of your library. If you do, return target permanent card from your graveyard to your hand.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
Haste

Whenever a creature enters, it fights another target creature of its controller's choice.

Deathtouch
When The Terror of Shady Cove enters, target opponent sacrifices an artifact. If they can't, create a 3/3 green Slug creature token with deathtouch. Then repeat this process for an enchantment and a nonbasic land.

As long as it's your turn, Defect 37 is a 7/7 Vehicle artifact with crew 2.
[+1]: Creatures and Vehicles you control get +1/+1 until end of turn.
[–1]: Put target permanent into its owner's library, third from the top. If Defect 37 is on the battlefield, return her to her owner's hand.
[–6]: Until end of turn, each noncreature, nonland permanent you control becomes a creature in addition to its other types with base power and toughness each equal to their mana value or base power, whichever is greater.

Whenever a Survivor you control enters, you may draw a card. If you do, discard a card.

[+1]: Raidragos, the Vindictive deals 3 damage to target player or planeswalker and 1 damage to you.
[–2]: Until end of turn, creatures you control gain “{R}: This creature gets +1/+0 until end of turn.”
[–8]: You get an emblem with “Whenever you cast an instant or sorcery spell, this emblem deals 4 damage to each opponent.”