msem-instigator

{T}: Return target creature card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. That creature salvages a card. (Exile one from your graveyard until that creature leaves the battlefield. Whenever that creature deals combat damage to a player, put a card it salvaged into your hand.)

Whenever Wakeborne Kraken or another Kraken, Leviathan, Octopus, or Serpent you control enters, you may return target creature an opponent controls to its owner's hand.
Whenever a creature an opponent controls leaves the battlefield, if it didn't die, draw a card.

Whenever Watch Me Burn enters or another source you control deals noncombat damage, put an ignition counter on Watch Me Burn. Then it deals damage equal to the number of ignition counters on it to each opponent.

Changeling (This card is every creature type.)
Watcher of the Polyps has all names of creature cards in addition to its name as long as it's on the battlefield.
Watcher of the Polyps gets +X/+X, where X is the greatest number of creatures you control with the same name.

Vigilance
Whenever Watchful Navigator crews a Vehicle, that Vehicle gets +1/+1 and gains vigilance until end of turn.

Each other creature you control that's a Merfolk or an Elemental gets +1/+1.
Whenever you cast an instant, sorcery, or Merfolk spell, you may pay {1}. If you do, create a 1/0 blue Elemental creature token.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{3}{U}: Target creature gains slipstream until end of turn.

Pressure {3}{G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Put two +1/+1 counters on target creature you control if Way of the Danithra was cast for its pressure cost. Then it fights up to one target creature you don't control.

Counter target spell if you have more cards in your graveyard than that spell's controller.

Whenever West Ward Purifier becomes tapped, you gain 1 life.

Destroy target artifact or enchantment.
Cycling {2} ({2}, Discard this card: Draw a card.)

Prowess
Curse spells you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Whenever you cast a Curse spell, you may draw a card.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
When Xifang Hu enters, noncreature spells cost {2} more to cast until your next turn.
{1}{W}: Demigod — Whenever a creature attacks this turn, create a 1/1 colorless Spirit creature token.
{4}{W}{W}: God — Distribute a flying, first strike, indestructible, lifelink, vigilance, and +1/+1 counter among any number of creatures you control.

Whenever you draw your second card each turn, put a +1/+1 counter on Youthful Tortoise.
Cycling {2} ({2}, Discard this card: Draw a card.)

Lifelink
Spells your opponents cast cost an additional {1} to cast for each spell they've cast before it this turn.

Whenever a nontoken creature you control dies, create a 1/1 black Spirit creature token with flying.
[+1]: Each opponent loses 2 life and you gain 2 life.
[–2]: You may sacrifice a creature. When you do, destroy target nonland permanent.

First strike, haste
At the beginning of each end step, if a player lost life this turn, put a +1/+1 counter on Animara, Last of the Fell.

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

[+1]: Create a green enchantment token named Swarm with “At the beginning of your end step, create a 1/1 green Insect creature token.”
[–2]: Create a green enchantment token named Survive with “Whenever a creature you control dies, you gain life equal to its power.”
[–4]: Create a green enchantment token named Scrounge with “Whenever a creature you control enters, draw a card.”

{T}, Sacrifice Camahueto Calf: Return target land card from your graveyard to the battlefield.

Whenever you cast a noncreature spell, if you control exactly one creature, copy that spell. You may choose new targets for the copies. (If it's a permanent, it resolves as a token.)

[+2]: You may sacrifice a permanent or discard a card. If you do, draw a card.
[–X]: Return target creature card with mana value X or less from your graveyard to the battlefield.
[–8]: You get an emblem with “Whenever a permanent you control dies, return a permanent card with lesser mana value from your graveyard to the battlefield.”

Sacrifice a creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Tap two untapped Elves you control: Add {G}{G}.
{6}{G}{G}: Create an 8/8 green Elemental creature token.

Whenever a player searches their library, that player can't untap more than two permanents during their next untap step.