msem-instigator

Choose target creature you control. Mill cards equal to its power, then it fights up to one target creature you don't control.

When this creature enters, put two -1/-1 counters on a creature you control.
{T}, Sacrifice another creature: Add {C}{R}. Spend this mana only to cast creature spells or activate abilities of creatures or creature cards in your graveyard.

{T}: Put a +1/+1 counter on Tender of Gardens. Activate only as a sorcery.

Whenever Consuming Doom or another enchantment you control enters, you may have target creature get -1/-1 until end of turn.
Whenever a source an opponent controls destroys an enchantment you control, that player sacrifices a creature.

First strike (This creature deals combat damage before creatures without first strike.)

Mianju enters with your choice of a menace or +1/+1 counter on them.
Whenever two or more creatures in Mianju's pack attack, mill three cards, then return a creature card from your graveyard to your hand. (Two or more creatures you control with equal power are in a pack.)

Return target creature card from your graveyard to your hand.

You draw two cards, lose 2 life, and create a Gold token. (It's an artifact with “Sacrifice this artifact: Add one mana of any color.”)

This spell costs {1} less to cast for each ten cards in your library.
Take an extra turn after this one.
Exile Temporal Insight.

At the beginning of your end step, for each permanent with exactly one counter on it, you may choose one —
• Remove all counters from that permanent.
• Choose a kind of counter on that permanent. Put another counter of that kind on that permanent.

Shuffle your library, then exile cards from the top until you've exiled cards with total mana value greater than or equal to X. You may play those cards until the end of your next turn. Add X mana of any one color.
Exile Final Ballad.

Mill three cards, then return an artifact or creature card from your graveyard to your hand.

Target creature gets -2/-2 until end of turn.
Dominance — That creature gets -4/-4 until end of turn instead if you control the creature with the greatest power or tied for the greatest power.

Slaughterkeg can't attack or block.
While an opponent is choosing targets as part of casting a spell they control or activating an ability they control, that player must choose at least Slaughterkeg if able.
When Slaughterkeg dies, draw a card.

Flash
When you cast Aether Ascendant, you may have it become a copy of target instant or sorcery spell. If you do, choose new targets for it. (It won't enter.)

Destroy target enchantment and all other enchantments with the same name as that enchantment.
Draw a card.

During your turn, Helene is a 4/4 Human Warrior creature with hexproof and trample that's still a planeswalker. Prevent all damage that would be dealt to her during your turn.
[+1]: Create a green Stance enchantment token with “When a creature you control deals combat damage to an opponent, sacrifice this. If you do, draw a card.”
[–2]: Create a blue Stance enchantment token with “When an opponent casts a noncreature spell, sacrifice this. If you do, counter that spell.”

When Final Form enters, your life total becomes 20.
At the beginning of your upkeep, destroy up to one target creature. You draw X cards and you lose X life, where X is its power.

Whenever a land you control enters, crystallize.
{10}: Shuffle any number of other permanents you control into their owner's library. Mill that many cards. Put all permanent cards milled this way onto the battlefield. Activate only during your turn and only once each turn.

Garden Cherub's power and toughness are each equal to the number of creatures you control.
Garden Cherub can't be blocked by creatures with power 2 or less.

Creatures you control get +1/+0 until end of turn. (Then exile this card. You may play the land later from exile.)

Each nontoken land you control has all activated abilities of each other land on the battlefield.
When Idyll leaves the battlefield, until the end of your next turn, you gain “Each nontoken land you control has all activated abilities of each other land on the battlefield.”

When Crystal Vision Abomination enters, create a 1/1 blue Elemental creature token with flying.
Whenever an Elemental you control attacks, that creature gets +1/+0 and first strike until end of turn.

Pay 3 life: Put a +1/+1 counter on target creature.

Up to one target creature gets +1/+1 and gains trample until end of turn. Put a -1/-1 counter on up to one target blocking or blocked creature.