msem-instigator

Whenever a player casts a creature spell, they sacrifice a creature.
Revive—{3}{B}{G}, Sacrifice a creature. ({3}{B}{G}, Sacrifice a creature, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Prowess
Whenever Steamwalker attacks, you may discard a card. If you do, draw a card, then catalyze. (The next spell you cast this turn costs {1} less to cast.)

Return target creature card from your graveyard to the battlefield.
Fuse (You may cast one or both halves of this card from your hand.)

Exile target card from a graveyard. Create a 1/1 black Worm creature token.
Fuse (You may cast one or both halves of this card from your hand.)

Each player puts the bottom five cards of their library into their graveyard.
Fuse (You may cast one or both halves of this card from your hand.)

Each player sacrifices a creature and discards a card.
Fuse (You may cast one or both halves of this card from your hand.)

Target creature gains flying and gets +1/+0 for each card in your hand until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Until end of turn, target creature gains double strike and damage dealt by it can't be prevented.
Fuse (You may cast one or both halves of this card from your hand.)

Target creature gains indestructible until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

If target creature would leave the battlefield this turn, return it to its owner's hand instead.
Fuse (You may cast one or both halves of this card from your hand.)

Sword deals 2 damage to any target.
Fuse (You may cast one or both halves of this card from your hand.)

Target creature gets +2/+2 until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Flash
Haste
{3}, {T}: Exchange control of two target noncreature spells. Their controllers may choose new targets for the spells.

Bronze Giant has trample as long as you control a token creature.

Equipped creature has “{T}, Sacrifice this creature: Return target creature card from your graveyard to the battlefield.”
Equip {5}
Equip {1}{B}{B}

Play with the bottom card of your library revealed.
Whenever you cast a spell or play a land from your hand that shares a type with the bottom card of one or more of your libraries, you may cast each of those cards without paying its mana cost or put it onto the battlefield if it's a land.

{2}: Duela Duelist gains first strike until end of turn.
{3}: Duela Duelist gains distorted until end of turn. (This creature can be blocked by tapped creatures but not untapped creatures.)

Whenever you cast an instant or sorcery spell, you may untap Duela Science Kit.
{T}, Tap an untapped creature you control: Catalyze. (The next spell you cast this turn costs {1} less to cast.)

{2}, {T}: Reveal the bottom card of your library. You gain life equal to its mana value. You may put it into your graveyard.

Equipped creature has first strike.
{R}: Equipped creature gets +1/+0 until end of turn.
Equip {2}

Equipped creature gets +0/+2 and has flying.
Equip {2}

{T}: Look at the top and bottom card of your library. Put up to one on top of your library and the rest on the bottom in any order.
{2}: Mill a card.

Equipped creature gets +1/+1. If it's a token, it gets +3/+3 instead.
Equip {2}

When you cast an instant or sorcery spell, you may sacrifice Shard Flower. If you do, copy that spell. You may choose new targets for the copy.

Equipped creature gets +1/+1 and has distorted. (It can be blocked by tapped creatures but not untapped creatures.)
Equip {1}