msem-instigator

Whenever you gain life, each opponent loses 1 life.

Destroy all monocolored creatures.

Haste
Whenever two or more creatures you control deal combat damage to a player, tap those creatures, then gain control of target creature you don't control until end of turn. Untap that creature. It gains haste until end of turn. After this phase, there's an additional combat phase.

This spell can't be countered.
Whenever one or more creatures with flying attack, upgrade Guided Sniper. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Reach
• Hexproof

Choose two —
• Each opponent sacrifices a creature with mana value 3 or less.
• Each opponent sacrifices an enchantment with mana value 3 or less.
• Exile each opponent's graveyard.
• You gain 3 life.

Flying
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Peasant Crusher can't be blocked by creatures with power 1 or less.

When Sentient Contraption enters, create a 1/1 colorless Thopter artifact creature token with flying.

{T}: Add {C}.
{T}: Add {C}{C}. You can't spend this mana to cast spells or activate abilities of lands.

When you cast this spell, copy it. You may choose new targets for the copy. (Copies keep functions.)
Draw a card.

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

{4}, {T}, Sacrifice Yenzu Ritual Vessel: Yenzu Ritual Vessel deals 4 damage to target creature or planeswalker.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever you cast an enchantment, instant, or sorcery spell, Noble Barracuda gets +1/+0 until end of turn. Scry 1.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds one mana of any color.

Partner with Kasoha, Keeper of Truths (When this creature enters, target player may put Kasoha into their hand from their library, then shuffle.)
Whenever Shizura, Keeper of Traditions or another legendary creature dies, target player draws two cards and loses 2 life.

Prowess
Whenever you cast a noncreature spell, Noxan Pilgrim gains lifelink until end of turn.

Until end of turn, target creature gets +3/+0 and gains “When this creature dies, return it to the battlefield tapped under its owner's control.”
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create four 1/1 colorless Construct Actor creature tokens.
II — Each player sacrifices a nontoken creature.
III — Each player loses 3 life.

The first artifact spell you cast each turn costs {2} less to cast.
The first ability of an artifact you activate each turn costs {T} less.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Facsimile Sculptor desecrates a permanent, create a token that's a copy of another target creature you control, except it's an artifact (not a creature).

Flash
Excess damage Polarity Sage would deal to an attacking creature is dealt to that creature's controller instead.

Enchant opponent
Creatures enchanted player control lose hexproof and indestructible and can't have or gain hexproof or indestructible.

Prevent all combat damage that would be dealt this turn by non-Army creatures.
Amass Soldiers 2. (Put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Flying
Whenever Havengul Banshee attacks, each creature defending player controls gets -1/-0 until end of turn.
{3}{U}: Return Havengul Banshee from your graveyard to the battlefield transformed under your control attached to target opponent. Activate only as a sorcery.

Return up to two target creature cards from your graveyard to your hand.