msem-instigator

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Tegan, the Sparrowhawk attacks, you may pay {R/W}. When you do, Tegan deals 1 damage to target creature if it's tapped. Otherwise, tap it.

{8}: Exile target nonbasic permanent. Its controller gains life equal to its mana value.

Flash
When Tenvilu, Earthen Warden enters, other creatures you control get +2/+2 and gain hexproof and indestructible until end of turn.

Terra Novea's power and toughness are each equal to the number of permanents you control.
{T}: Add {G} for each land you control.

First strike
Thailen, Heir to Daeland's power is equal to the number of other attacking or blocking creatures you control.

Flying
At the beginning of combat on your turn, gain control of up to one target creature an opponent controls. If you do, untap it, and it gets +4/+4 and gains flying and haste until end of turn. Sacrifice it at the beginning of the next end step.

Flying, lifelink
Whenever you gain life, each opponent loses 1 life.
{4}{B}{B}: Create a 1/1 black Vampire creature token with lifelink for each nontoken creature that died this turn.

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of each combat, you may tap or untap another target nonland permanent.
{2}{U}: Create a 1/1 blue Merfolk Rogue creature token with “{T}: Draw a card, then discard a card.”

Menace
When The Anguilahydra enters, draw X cards and put X +1/+1 counters on The Anguilahydra, where X is the number of enchantments you control.

Haste, prowess
Whenever you cast a noncreature spell, journey. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to an opponent, put a journeyed card you own into your hand.)

Menace
Whenever a creature dies, you gain life equal to its power.
Reappropriate: Put a +1/+1 counter on The Cannibals of Kallio Hill, then lose life equal to its power. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

Other permanents you control have hexproof.
Prevent all damage that would be dealt to other permanents you control.

First strike
At the beginning of your end step, each opponent that lost life this turn loses 1 life and discards a card. You gain life equal to the life lost this way, then draw a card for each land card discarded this way.

Whenever The Dreamer enters or you play a card exiled with them, exile the top two cards of your library face down, then another face up.
You may play face up cards exiled with The Dreamer.
{T}, Sacrifice The Dreamer: Look at each face down card exiled with The Dreamer. You may cast one without paying its mana cost.

Flying, menace
Whenever another creature you control deals combat damage to a player, sacrifice it.
If you would draw a card, you may instead return a creature card from your graveyard to your hand.

Menace
When The Duneborn Host enters, mill four cards.
Whenever a card is put into your graveyard from anywhere, each opponent loses 1 life and you gain 1 life.
Whenever a card leaves your graveyard, create a 2/2 black Zombie creature token.

Cards in graveyards, exile, and libraries lose all abilities and card types.

Whenever The Feller of Greatwoods enters or attacks, you may sacrifice two noncreature permanents. For each permanent sacrificed this way, reveal the top five cards of your library. You may put a creature card from among them onto the battlefield and the rest into your graveyard.

Whenever The First Idol attacks, 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.”)
Sacrifice three Idols: Return The First Idol from your graveyard your hand.

Whenever an opponent activates an ability of a nonland permanent, destroy that permanent.
{3}{U}{B}{R}: Exile target creature or planeswalker card in a graveyard. Create a token that's a copy of it.

Flying
When you cast The Grand Simurgh, search your graveyard and the top five cards of your library for any number of nonlegendary creature cards with total mana value 5 or less and put those cards onto the battlefield, then shuffle.

First strike
Whenever The Heart-hardened or another creature you control dies, each opponent loses 1 life. If this is the third time this ability has resolved this turn, you draw three cards and you lose 3 life.

Trample
Whenever a creature you don't control dies, you gain 2 life.
Whenever you gain life, put that many +1/+1 counters on target creature you control.

Flash
Hexproof
{3}, Exile two cards from your graveyard: Gain control of target spell or permanent if it shares a type with both of those cards.

Flying
You pay {0} to cast your first spell each turn rather than its mana cost. If you cast a spell with {X} in its mana cost this way, X is 8.