msem-instigator

Equipped creature gets +2/+1.
Whenever equipped creature attacks, you draw a card and you lose 1 life.
Equip Knight or Soldier {1}
Equip {3}

When Skittering Atrocity enters, up to one target creature gets -X/-X until end of turn, where X is the number of Horrors you control.

Smelting Breath deals 5 damage to target creature. Destroy up to one Equipment attached to that creature.

Exile target creature. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.

Target creature you control gains trample until end of turn. Whenever that creature deals damage to a player this turn, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Whenever Lotus Acolyte attacks, it gets +1/+0 and gains lifelink until end of turn.

Flash
When Mennin Pack enters, each opponent loses 1 life.
When Mennin Pack dies, each opponent discards a card.

Sacred Summits enters tapped.
{T}: Add one mana of any color among the color identity of legendary creatures and planeswalkers you control or legendary cards in your command zone.

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
{5}{B}, Sacrifice Manipulations of the Div: It deals 4 damage to target player or battle and you gain 4 life. Activate only as a sorcery.

Once each turn, when you activate a nonmana ability, you may gain 1 life and draw a card.
{2}{W}{U}: You may tap or untap target creature or artifact.

{T}, Sacrifice Phosphorescent Ravine: Search your library for an Island or Swamp card and put it onto the battlefield tapped, then shuffle.

When Pilgrim of Many Provinces enters, draw a card. Then you may discard a creature card. If you do, draw a card.

Surveil 1, then draw a card. (To surveil 1, look at the top card of your library. You may put that card into your graveyard.)
Create a tapped Treasure token.

Prowess, haste
When Embercore Grazer enters, add {R}{R}{R}. Spend this mana only to cast instant and/or sorcery spells.

Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
At the beginning of each player's upkeep, put a -1/-1 counter on target creature that player controls.

As an additional cost to cast this spell, sacrifice a land.
Creatures you control get +1/+1 and gain trample until end of turn for each land you control.

When Healing Potion enters, scry 1, then draw a card.
{2}, {T}, Sacrifice Healing Potion: You gain 4 life.

{B}, Discard a card: Post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

Magma Spray deals 2 damage to target creature. If that creature would die this turn, exile it instead.

If two or more creatures an opponent controls are attacking, you may pay {B} rather than this spell's mana cost.
Create a 1/1 black Snake creature token with deathtouch. It gains first strike until end of turn.

Enchant creature with flying
Enchanted creature can't attack or block, and it loses all abilities other than flying.

Other creatures you control get +1/+1 as long as you control four or more lands.
{G}, Sacrifice Daisy, the Heart of Chasmek: Creatures you control with base power 1 or less gain indestructible until end of turn.

Prowess, trample
Whenever Brilliant Diviner deals combat damage to a player, draw a card.

Primal {R} (During your turn, you may cast this spell for {R} instead of playing a land.)
Target creature gets +4/+0 and gains trample until end of turn.

Flying
When Rooftop Robber enters, another target Pirate or Rogue you control gets +2/+0 and can't be blocked this turn.