msem-instigator

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Menace
When this creature enters, put a -1/-1 counter on a creature you control.

Target opponent exiles a card from their hand. If this spell was cast from a graveyard, instead look at that player's hand, you choose a nonland card from it, then exile that card.
Flashback {2}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Creatures you control get +2/+2 until end of turn.

Trample, hexproof

Flying
Civilized — Whenever Aven Supervisor deals combat damage to a player, if you control an artifact, a creature, and an enchantment, you may draw a card. If you do, discard a card.

Prowess, haste

Equipped creature and creatures you control that share a name with it get +1/+0.
Whenever equipped creature attacks, create a tapped and attacking token that's a copy of that creature, except it's not legendary. Exile that token at the beginning of the next end step.
Equip {2}

{W}, {T}: Tap target creature.

{T}, Tap an untapped creature you control: Choose one —
• Add one mana of any color.
• Target player loses 2 life.
• Target player gains 3 life.
• Target player mills four cards.

Trample
{1}{B}: Rehis-Dorahn Plowbeast gets +1/+1 until end of turn.

Flying

Haste
Whenever Rapid Rodent attacks, it gets +1/+0 until end of turn for each other creature you control with flash and/or haste.

This spell costs {3} less to cast if it targets a creature with mana value 2 or less.
Destroy target creature.

Target player reveals their hand. Exile a nonland card from it and put a secret counter on it. As long as that card remains exiled, that player may pay {2} any time they could cast a sorcery to put it into their hand.
{X}{B}{B}, Exile Swipe Secrets from your graveyard: Until end of turn, you may cast target card you exiled with a secret counter on it and mana value X without paying its mana cost.

Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Leonin Sandfighter enters, if tribute was paid, it gains first strike. Otherwise it gains double strike. (This effect lasts indefinitely.)

Target opponent reveals their hand. You choose a nonland card from it. Exile that card. You lose 2 life.
Augmented — Then if you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may cast that card without paying its mana cost.

[+1]: Add {W}{U}{B}{R}{G}.
[–1]: Exile the top three cards of your library. Until end of turn, you may play cards exiled with this permanent.
[–3]: Create a 5/5 Archon creature token that's all colors and has flying and “When this creature enters, it deals 5 damage to any target.”

Menace, haste

Tap up to two target creatures.
Flashback {3}{W/U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

You may pay {1}{G} and tap an untapped Soldier you control rather than pay this spell's mana cost.
Put two +1/+1 counters on target creature. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Destroy target creature with flying. Judge up to one target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

Target creature gets +2/+1 and gains trample until end of turn. Create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Cradle of Corruption enters tapped.
Whenever a creature dies, put a creation counter on Cradle of Corruption.
{T}, Remove ten creation counters from Cradle of Corruption and sacrifice it: Put up to two target creature cards from graveyards onto the battlefield under your control. Activate only as a sorcery.

When Globule of Intuition enters or leaves the battlefield, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)
{2/U}, {T}, Sacrifice Globule of Intuition: Draw a card.