msem-instigator

Counter target spell unless its controller pays {4}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

At the beginning of each opponent's end step, that player gets a poison counter unless damage was dealt this turn.

Mind Palace enters tapped.
{T}: Add {U} or {B}.
When Mind Palace enters, you may put a loyalty counter on a planeswalker you control.

Return target creature card from your graveyard to your hand.
Draw a card.

Spells you cast from anywhere other than your hand can't be countered.
Whenever an opponent casts a spell with the same name as a card they own in exile or in their graveyard, you may draw a card.

Enchant creature
When Kalku Initiation enters, you lose 3 life and discard a card.
Enchanted creature gets +3/+2, has ward {2}, and has “Whenever this creature deals damage to a player, draw two cards.”

({T}: Add {G} or {U}.)
As Ruptured Grove enters, you may pay {1}. If you don't, Ruptured Grove enters tapped.

Menace
Sacrifice another artifact: Scrap Buggy becomes an artifact creature until end of turn.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

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

Pressure {3}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
When Oryxyth's Brood enters, you draw two cards and you lose 2 life.

Equipped creature has “You may choose not to untap this creature during your untap step” and “{T}: Gain control of target creature with power 5 or greater for as long as you control this creature and it remains tapped.”
Equip {3}

Whenever Rustshell Mantis is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
{2}{G}: Crazed Sprareos gets +2/+2 until end of turn. Activate only once each turn.

Flying
When Departed Butler enters, draw a card.

When Gluttonous Empath enters, gain control of target nonland permanent for as long as you control Gluttonous Empath.

Target player reveals their hand. Exile a nonland card from it and put a secret counter on it. As long as that card remains exiled, that player may pay {2} any time they could cast a sorcery to put it into their hand.
{X}{B}{B}, Exile Swipe Secrets from your graveyard: Until end of turn, you may cast target card you exiled with a secret counter on it and mana value X without paying its mana cost.

Exile up to two target permanents you control, then return those cards to the battlefield under their owner's control.
Audition for blue. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)

{T}: Add {C}.
{4}, {T}: Create a 0/1 white Goat creature token.
{T}, Sacrifice X Goats: Add X mana of any one color. You gain X life.

{2}, {T}, Sacrifice a creature: Each opponent loses 2 life. You gain life equal to the life lost this way.

Once each turn, if a triggered ability of another legendary permanent you control would trigger, you may have it trigger an additional time.

Whenever you cast an instant or sorcery spell, exile cards from the top of your library until you exile an instant or sorcery card. You may cast that card until you exile another card with this ability.

Choose one —
• Exile target creature with flying.
• Exile up to three target cards from a single graveyard. Draw a card.

{2}, {T}, Sacrifice Cartographer's Chart: Search your library for a land card, reveal it, and put it into your hand, then shuffle.
{2}, {T}, Sacrifice Cartographer's Chart: Draw a card.

Whenever Tortle Veteran or another Turtle you control enters, that creature 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 creature, then put the card back or put it into your graveyard.)

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.