msem-instigator

{R}: Phyrexian Firemaster gains haste until end of turn.

Scry 3, then reveal the top card of your library. If it's a creature card, Hunter's Instinct deals damage to target creature equal to the revealed card's power.
Ferocious — If the revealed card is a creature card with power 4 or greater, put it into your hand.

Target player sacrifices an attacking or blocking creature. Prevent all damage that would be dealt by creatures this turn.

Choose one —
• Forgemaster's Charm deals X damage to target creature.
• Destroy X target artifacts.
• Create an X/X colorless Juggernaut artifact creature token.

({T}: Add {U} or {R}.)
Whenever Crystal Cavern becomes tapped, you lose 1 life unless you control two or more basic lands.

Exile target spell or nonland permanent. That card's owner casts it without paying its mana cost at the beginning of the next turn's upkeep.

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, Betrayer's Mantle deals 3 damage to that player.

{T}: Add {G}.

Exile the top two cards of your library. You may play those cards until the end of your next turn. Whenever you play one of those cards, rouse 1. (Put a +1/+1 counter on a permanent you control. If it isn't a creature, tap it and it becomes a 0/0 creature in addition to its other types.)

Prowess
{1}{R}: Until end of turn, if an instant, sorcery, or Dragon source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead. Activate only once each turn.

When Shaidostan Cryoforger enters, exile the top card of your library.
When Shaidostan Cryoforger dies, you may put the exiled card into your hand.

Battalion — Whenever Callous Trainer and at least two other creatures attack, create a 1/1 white Warrior creature token that's tapped and attacking.

Each player sacrifices a creature.
Coalesce {5}{B} (You may cast this from your graveyard for {5}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Sacrifice any number of permanents. If five colors were among the sacrificed permanents, each player exiles the top five cards of their library. For each player, you may cast up to two cards they exiled this way without paying their mana costs.

Destroy target tapped creature.
Menagerie — If there are five or more creature types among creatures you control, that creature's controller discards a card.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever a creature blocks, its controller loses 1 life.

Marin Polgek, Academy Heiress has hexproof as long as you control three or more enchantments.
{1}{W/U}{W/U}: Create a token that's a copy of target enchantment you control.

Equipped creature gets +2/+1.
Whenever equipped creature becomes untapped, you draw a card and you gain 2 life.
Equip {3}

Draw a card, then create a 1/1 blue Elemental creature token. If you drew three or more cards this turn, create three of those tokens instead.

{T}, Sacrifice a creature: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{T}, Sacrifice a Clue: Create a 3/3 green Elemental creature token.

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Slopestrider's Chariot's rider gets +1/+1 and has double strike.

During your opponents' turns, Chroma, the Faerie Circle has all basic land types in all zones.
Chroma, the Faerie Circle enters tapped.

Destroy target creature.

Whenever Icepeak Phantasm becomes the target of a spell or ability, an opponent may pay {2}. If they do, sacrifice it.

Clockwork Gaucho enters with a +1/+1 counter on it.
Other artifact creatures you control get +1/+1 for each +1/+1 counter on Clockwork Gaucho.
{T}: Put a +1/+1 counter on Clockwork Gaucho.