msem-instigator

Sacrifice a creature: Exile the top card of your library. Until end of turn, you may play that card.

Menace (This creature can't be blocked except by two or more creatures.)
Avatar of Basat can't block.

{T}: Add {C}.
Satrapies you control have “{1}{R}, {T}, Discard a card: Draw a card.”

Avaz Sanctuary enters the battlefield tapped.
Satrapies you control have “{T}: Add {R} or {W}.”

Avaz Temple enters the battlefield tapped.
Satrapies you control have “{T}: Add {R} or {G}.”

Counter target instant or Aura spell that targets a permanent you control.

As an additional cost to cast this spell, exile a red card from your hand.
Destroy target artifact. Awaken to the Skies deals damage to that artifact's controller equal to its mana value.

{R}, {T}: Put a luster counter on Awestone.
{1}{R}, {T}: Add {R} for each luster counter on Awestone.
{2}{R}, {T}: Until end of turn, gain control of target nonland permanent with mana value less than or equal to the number of luster counters on Awestone and it gains haste. Untap that permanent. Activate only during your turn.

Target opponent shuffles a card from their hand into their library.

You may cast target instant card from your graveyard this turn. If a card cast this way would be put into your graveyard, exile it instead.

Target tapped creature gets -3/-3 until end of turn.

{T}, Pay 1 life: Add {R} or {W}.
{1}, {T}, Sacrifice Backstage Rooms: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Whenever you discard a card, exile that card from your graveyard.
{2}, {T}: Draw a card, then discard a card.
{4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.

Deathtouch
Bahet's Emissary gets +1/+1 as long as you control a white or black permanent.

Double strike
Engage (This creature must be blocked each combat if able.)
{1}{R}: Balanced Blade gets +1/+0 until end of turn.

Target creature gets +1/+0 and can't be blocked this turn.
Showcase {2}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Whenever equipped creature attacks, it gains deathtouch until end of turn.
Sacrifice Bandit's Dagger: Target player dealt damage by equipped creature this turn reveals their hand. You choose a nonland card from it. That player discards that card.
Equip {2}

Counter target planeswalker spell.
Draw a card.

Haste
Whenever Banished Companion attacks, it deals 2 damage to you.

Battalion — Whenever Barbarian Rager and at least two other creatures attack, Barbarian Rager gets +2/+0 until end of turn.

{2}{B}, Exile Barbed Cocoon from your graveyard: Create two 1/1 green Insect creature tokens. Activate only as a sorcery.

Barbed Reef enters the battlefield tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {B}.
{4}{B}: Barbed Reef becomes a Jellyfish creature. (This effect lasts indefinitely.)

Barren Boneyard enters the battlefield tapped.
{T}: Add {B}.
{2/B}{2/B}: Barren Boneyard becomes a 2/3 black Elemental creature with deathtouch until end of turn. It's still a land.

As Barren Desolation enters the battlefield, you may pay 2 life. If you don't, Barren Desolation enters the battlefield tapped.
{T}, Sacrifice Barren Desolation: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Barren Vista enters the battlefield tapped.
{T}: Add {U} or {B}.
{1}, {T}: Add one mana of any color.