msem-instigator

Target player discards a card and loses 2 life.
Draw a card.

Flying, deathtouch

Rapport — Whenever Ainok Brushwacker and at least one other creature you control become tapped, Ainok Brushwacker gains first strike until end of turn.

Colossal 3—{4}{R}{G} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {4}{R}{G} as a sorcery: Put three +1/+1 counters on it if it has none.)
Each creature you control with a counter on it can't be blocked by more than one creature.

Lifelink
Partner with Imperator Valtasius (When this creature enters, target player may put Imperator Valtasius into their hand from their library, then shuffle.)
At the beginning of your upkeep, return target Soldier card from your graveyard to your hand.

Flying
At the beginning of combat on your turn, create a 5/5 red Dragon creature token with flying and haste. That token attacks this combat if able.

Haste
Heroic — Whenever you cast a spell that targets Akroan Siege Captain, put a +1/+1 counter on each creature you control.

Flying
When a creature you control scavenges Carrion Courier, put a flying counter on that creature.
Scavenge {2}{B} ({2}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Harvest (You may tap any number of creatures you control as you cast this spell. If you do, reduce this spell's mana cost by their total power.)
Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. You gain 3 life.

Flying, haste
Whenever Eavesknocker attacks, another target attacking creature gets +1/+1 until end of turn.

When Pious Flutist enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
You gain X life.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds one mana of any color.

[+1]: Reveal the top card of your library. If it doesn't have the same name as a card in your graveyard or a permanent you control, put it into your hand. Otherwise, put it into your graveyard.
[–2]: Return target card from your graveyard to your hand.
[–8]: Return all other cards from your graveyard to your hand. Until end of turn, spells you cast cost {5} less to cast.

Target player reveals their hand. You choose a nonland card from it. That player discards that card. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When Seeker of Far-Off Lands enters, search target opponent's library for a land card, put it onto the battlefield tapped under your control, then that player shuffles.

Golden Company Valiant can block any number of creatures.
At the beginning of combat on each opponent's turn, Golden Company Valiant gets +1/+1 until end of turn for each creature that player controls.

When Hannaru's Spear enters, create Hannaru's Aegis, a legendary white Equipment artifact token with “Equipped creature gets +1/+2 and has vigilance” and equip {2}.
Equipped creature gets +2/+1 and has first strike.
Equip {2}

Flying
Whenever Prismatic Scyphozoa attacks or blocks, target player mills three cards.
When Prismatic Scyphozoa dies, create four 1/1 blue Elemental creature tokens with flying.

When Atrocity of Flesh enters, destroy target nonland permanent.
When Atrocity of Flesh dies, you may exile it. If you do, return target card from your graveyard to your hand.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever an opponent loses 3 or more life, add a quest counter.
1 — Destroy up to one target creature with power or toughness 2 or less.
2 — Create Sir Jasper Reborn, a legendary 3/1 black Zombie Mouse Knight creature token with menace.
3 — Search your library for a card, reveal it, put it into your hand, then shuffle. If you revealed a card named Karoa's Downfall this way, you may cast it without paying its mana cost.

Hexproof

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Trample

Whenever you activate a loyalty ability of Xanigan, the Darkened Cloud, you get an emblem with exalted.
[+2]: Xanigan deals 2 damage to up to one target and you gain 2 life.
[–3]: You draw three cards and you lose 3 life.
[–7]: Xanigan becomes a 7/7 Demon creature with flying and indestructible that's still a planeswalker. Prevent all combat damage that would be dealt to her.

Target creature gets +2/+2 until end of turn. If you cast this spell from exile, that creature gets +4/+4 and gains trample until end of turn instead.
Prophecy {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.)