msem-instigator

Azun's Play deals damage to any target equal to the number of cards in your hand.
Quickdraw {R}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {R}{R}.)

Riga's Workshop enters tapped.
When Riga's Workshop enters, you may mill two cards.
{T}: Add {U} or {R}.

Target creature you control deals damage equal to its power to target creature with flying.

{U}, Sacrifice Results Uncertain: Scry 2.
{U}, Sacrifice Results Uncertain: Draw a card.

Create three 1/1 blue and red Pirate creature tokens with haste.

Flash (You may cast this spell any time you could cast an instant.)
When Replicator Mage enters, you may create a token that's a copy of target creature that's attacking you. Exile that token at end of combat.

If a creature dealt damage by equipped creature this turn would die, exile that card and draw a card instead.
Equip {1}

Lifelink, haste
Equip abilities that target Rose of Sunspear cost {X} less to activate, where X is her power.

Trample
Whenever Simian Sentinel attacks, it gets +X/+0 until end of turn, where X is the number of lore counters on Sagas you control.

Target opponent reveals cards from the top of their library until they reveal two instant and/or sorcery cards. Exile those cards, then that player shuffles the rest into their library. You may cast cards exiled this way until end of turn, and you may cast them without paying their mana costs.

Flying
{3}{W}: Scry 2. You gain 2 life.

Target player chooses a creature they control, then returns all other creatures they control to their owners' hands.

When Dthan's Daggers enters, you may attach it to target creature you control.
Whenever equipped creature attacks, it gets +3/+0 and gains first strike until end of turn.
Equip {3}{R}

{W}, Sacrifice Haunting Bard: Destroy target artifact or enchantment.

When Fox of the Molten Dawn enters, you may return target Aura card with mana value 3 or less from your graveyard to the battlefield attached to a permanent it could enchant.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Whenever this creature attacks, target creature blocks it this combat if able.

(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 Soli Rising enters, reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order.

Whenever Evaldi's Muse or another nontoken creature you control enters, you gain 2 life.
When Evaldi's Muse leaves the battlefield, create two 1/1 green and blue Elf creature tokens.

When Hirukari's Immortal dies, if it didn't enter this turn, create a token that's a copy of it, except it has no mana cost.

Players can't cast spells with mana value greater than the number of dissent counters on Kazimir's Ban.
{2}: Put a dissent counter on Kazimir's Ban. Any player may activate this ability.

Whenever another creature you control enters, Loisch deals 1 damage to any target.
{4}{R}{G}: Loisch gets +X/+X and gains trample until end of turn, where X is the number of creatures you control.

Trample
Morph {6} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

When Mausoleum Rite enters, each player mills four cards.
{2}{B}, Exile a creature card from your graveyard: Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Undine Coven gets +1/+1 for each other Merfolk you control.
Whenever you cast a noncreature spell, Undine Coven deals 1 damage to target player or planeswalker.

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Put target creature [spell] on top of its owner's library.