msem-instigator

{2/U}, {T}: Target creature gets -4/-0 until end of turn.

Scavenge {5}{U} ({5}{U}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Trample
Gloamrazer Hydra enters with four +1/+1 counters on it.
Whenever a nontoken creature you control dies, if it was embattled, create an X/X green Hydra creature token, where X is that creature's power. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Enchant creature
When Imperative Blessing enters, draw a card.
Enchanted creature gets +2/+2.

Whenever Vedlinn Ross becomes tapped, exile a nonland card from target opponent's graveyard. Copy it. You may cast the copy this turn. (You still pay its costs, including color. Copies of permanents enter as tokens.)
Whenever you cast a spell from anywhere other than your hand, copy it. You may choose new targets for the copies.

Target player shuffles up to three target cards from their graveyard into their library.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Flying
{R}: Slyten Ignitor gets +1/+0 until end of turn.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Oslyd Heretic gets +1/+1 as long as you control no other creatures.

When Prince Crab enters, create a Treasure token and an Idol token. (An artifact with “{T}, Sacrifice this artifact: Add one mana of any color” and an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

You may exert Wiedfree Behemoth as it attacks. When you do, it gets +3/+3 and gains trample until end of turn. (An exerted creature won't untap during your next untap step.)

Whenever a nontoken creature you control dies, create a 1/1 black Worm creature token.
Sacrifice Fertile Grave: Create a 1/1 black Worm creature token.

Target creature you control gets +2/+1 until end of turn. It fights target creature you don't control. (Each deals damage to the other equal to its power.)

Emissary of Dai Gui enters tapped.
Emissary of Dai Gui doesn't untap during your untap step unless it's in a pack. (Two or more creatures you control with equal power are in a pack.)
Creature spells you cast cost {1} less to cast.

Enchant player
At the beginning of enchanted player's end step, if they cast a spell this turn, they lose 1 life.

Steel Hunter can't attack unless you control three or more other artifacts.

When Twilight of the Intisuyu enters, draw a card, then choose a card name.
Permanents you control with the chosen name have lifelink and ward {1}.

(As an Encounter enters, choose an opponent to protect it. You and others can attack it. When defense counters are removed, create a 0/0 Army token if you don't control one, then put that many +1/+1 counters on a Army you control.)
When Crisis in Kaneh enters, destroy up to one target creature or planeswalker.

Exile target artifact, creature, or enchantment. Return that card to the battlefield under its owner's control at the beginning of the next end step.
Draw a card.

Equipped creature has “{T}: Target attacking creature gets +1/+1 until end of turn.”
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

{1}{R}, {T}, Sacrifice an artifact: Elise, Maktali Prodigy deals 2 damage to any target.
{1}{U}, {T}, Sacrifice an artifact: Return target nonland permanent to its owner's hand.
{3}{U}{R}, {T}, Sacrifice three artifacts: Discard your hand, then draw seven cards.

When Arpechian Stag enters, create a 3/3 red Elk creature token with haste, a 3/3 green Elk creature token with trample, and a 3/3 white Elk creature token with vigilance.

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of your upkeep, each player discards a card. Then you draw a card. If an opponent can't discard a card or discarded a land card, you create a 2/3 red Minotaur creature token.

Vigilance, trample
Whenever you draw your second card each turn, put a +1/+1 counter on Coralblade Cohort.
Cycling {G} ({G}, Discard this card: Draw a card.)

Haste
When Jetskate enters, if you've drawn two or more cards this turn, it deals 2 damage to any target.
Cycling {R} ({R}, Discard this card: Draw a card.)

If you would create a token, you may instead create a tapped 2/2 green Faerie Bard creature token.
Whenever one or more creature tokens you control deal combat damage to a player, that player sacrifices an artifact or enchantment.