msem-instigator

Target creature gets -3/-3 until end of turn. When that creature dies this turn, its controller loses 2 life.

As an additional cost to cast this spell, sacrifice an artifact or enchantment.
You draw three cards and you lose 3 life.

When Gulch Custodian enters, return an artifact you control to its owner's hand.

When Gulch Glutton enters, create a 1/1 black Rat creature token.
Whenever Gulch Glutton perseveres, each player sacrifices a creature. (A creature perseveres when it survives damage.)

When Gulchdrinker Serpent enters, detain target permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Untap target creature you control. It fights target creature you don't control.

Enchant creature
Enchanted creature has double strike.
Whenever enchanted creature deals combat damage to an opponent, exile the top card of your library. You may play that card this turn.

Creatures you control get +2/+0 until end of turn. Each creature you control with a +1/+1 counter on it gains menace until end of turn.

Flash
When Guppyfin Duelist enters, create a green Aura enchantment token named Piranha's Prowess attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.” Untap that creature.

When Gusma's Artisan enters, search your library for a card, then shuffle and put that card on the bottom of it.
{2}{U}, Sacrifice Gusma's Artisan: Manifest the bottom card of your library. (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.)

{2}{B}, Sacrifice a creature: Manifest the bottom card of your library. (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.)
Whenever a creature you control is turned face up, it gains deathtouch until end of turn.

Prowess
Gusma's Emissary gets +1/+1 as long as you control a black or green permanent.

{B}{G}{U}, Discard a card named Gusma, God of Creation: Gusma gains indestructible and becomes a God creature in addition to its other types.
Whenever Gusma enters or attacks, add {B}{G}{U} and draw a card. You don't lose this mana as steps, phases, and turns end.

Flying
{1}{U}: Put Gustscreen Cherub on the bottom of its owner's library.
Morph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Destroy target nonland permanent.
If you've sacrificed a permanent this turn, draw a card.

Whenever an artifact enters or leaves the battlefield under your control, you gain 1 life.

At the beginning of combat on your turn, for each permanent type, aetherize up to one target permanent you control of that type. (To aetherize, create a token that's a copy of it, then exile that token.)

No more than one creature can attack each combat.
No more than one creature can block each combat.

Haste
Gyr, Awoken World has all activated abilities of other lands you control.
As long as Gyr, Awoken World is on the battlefield or in your graveyard, it's a land in addition to its other types.

When Gyreon Pickpocket enters, target opponent discards a card. If a land card was discarded this way, draw a card.

Exile up to one target nonland card from an opponent's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)
Draw a card.

Target creature you control deals damage equal to its power to target creature you don't control. If the creature you control is legendary, excess damage is dealt to that creature's controller instead.

Reach, trample
{1}{G}: You may remove a counter from a creature you control. If you do, tap that creature and it gains indestructible until end of turn.

{7}{G}: Distribute three +1/+1 counters among up to three target creatures you control. This ability costs {2} less to activate if you control a legendary creature.

Refine {3}{W}{B} (You may cast this spell by sacrificing an artifact and paying the refine cost reduced by that artifact's mana value.)
When H-9K Prototype enters, if it was refined, destroy target nonland permanent.