msem-instigator

When Flying Throne enters, attach it to target creature you control.
Equipped creature gets +1/+0 and has flying.
Equip {2}

Embellish {4}{W} (If you cast this spell for {4}{W}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
Equipped creature gets +2/+2.
Whenever an artifact creature you control enters, you may attach Etherium Staff to it.
Equip {2}

Flying, haste
Whenever Cyrukan's Elite attacks, create
a 4/4 white Angel Soldier creature token with flying. If it's the first time Cyrukan's Elite has attacked this turn, untap all creatures you control. After this phase, there is an additional combat phase.

This spell can't be countered.
Flying
Dominance — Whenever Stormwing Ultrateryx becomes the target of a spell an opponent controls, if you control the creature with the greatest power or tied for the greatest power, counter that spell.

Flash
When Slippery Assassin enters, counter target spell if its mana value is less than or equal to Slippery Assassin's power.
Sacrifice another creature: Put a +1/+1 counter on Slippery Assassin.

{1}, Exile Coiling Mystic from your graveyard: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Vigilance
When this creature transforms into Geist Whisperer, create two 1/1 white Spirit creature tokens with flying.
At the beginning of your end step, untap all Spirits and creatures with flying you control.

Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Whenever Mortified Medium or another creature enters, you gain 1 life.
As long as you have at least 10 life more than your starting life total, Mortified Medium gets +4/+4 and has flying.

Enchant creature you control
Whenever a land you control enters, put a +1/+1 counter on enchanted creature.
{3}{G}, Sacrifice Trace the Oasis: Draw cards equal to enchanted creature's power.

Put a +1/+1 counter on target creature. It gains indestructible until end of turn.

Flying, vigilance
At the beginning of your upkeep, if you control four or more Plains, put a +1/+1 counter on each other creature you control.

Breath of Hao'Tai deals 4 damage to any target.

Concord — As long as there are four or more card types among permanents you control, you may cast the first spell you cast each turn without paying its mana cost.

Mill X cards. Then you may return a creature card with mana value X or less from your graveyard to the battlefield.

{T}: Add {C}.
Ascend—Tap ten untapped permanents you control. (Tap ten untapped permanents you control: Exile this land, then return it to the battlefield transformed. Ascend only as a sorcery.)

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.

Flying, menace
When Dreadfire Tyrant enters, target opponent reveals their hand. You may put a creature or planeswalker card from it onto the battlefield under your control. That permanent gains haste and “At the beginning of your end step, sacrifice a permanent you control.”
When Dreadfire Tyrant dies, each opponent loses 5 life. You gain life equal to the life lost this way.

When Abberant Frostbringer enters, tap up to one target creature. If you do, put two stun counters on that creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the next end step.)

When Verdant Curtain Naturalist enters, you gain 3 life.
{T}: Add one mana of any color.

{T}: Add one mana of any color. Put a creation counter on Effigy of Ivory Fire.
{2}: Effigy of Ivory Fire becomes a 4/4 red Dragon artifact creature with flying until end of turn. Activate only if Effigy of Ivory Fire has three or more creation counters on it.

When Snarling Devil enters, create four 1/1 black Possum Dog creature tokens.
At the beginning of each upkeep, put your choice of a +1/+1, lifelink, menace, trample, or vigilance counter on a token creature you control.

{2}{W}: Ornate Legionnaire gains first strike until end of turn.

As Nimble Sandstorm enters, choose speed or power.
At the beginning of combat on your turn,
• Speed — Target creature gains haste until end of turn.
• Power — Target creature gets +2/+0 until end of turn.