Card

Katara, Water Tribe's Hope

Avatar: the Last Airbender Art Series

Avatar: The Last Airbender

Ally

Legendary Creature — Human Warrior Ally

Vigilance
When Katara enters, create a 1/1 white Ally creature token.
Waterbend {X}: Creatures you control have base power and toughness X/X until end of turn. X can't be 0. Activate only during your turn. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Final Fantasy

Enchantment Creature — Saga Wolf

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Crescent Fang — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Heavenward Howl — When you next cast a creature spell this turn, that creature enters with an additional +1/+1 counter on it.
III — Ecliptic Growl — Draw a card if you control the creature with the greatest power or tied for the greatest power.

Summon: Fenrir

Aetherdrift

Artifact Creature — Construct

Lifelink, ward {1}
When this creature enters, look at target player's hand. You may choose a card from it. If you do, that player discards that card, then draws a card.

Oildeep Gearhulk

Duskmourn: House of Horror

Creature — Plant

Delirium — Whenever this creature enters or attacks, if there are four or more card types among cards in your graveyard, distribute two +1/+1 counters among one or two target creatures. Then if there are six or more card types among cards in your graveyard, double the number of +1/+1 counters on those creatures.

Omnivorous Flytrap

Modern Horizons 3 Commander

Legendary Creature — Shapeshifter Noble

Whenever Omo enters or attacks, put an everything counter on each of up to one target land and up to one target creature.
Each land with an everything counter on it is every land type in addition to its other types.
Each nonland creature with an everything counter on it is every creature type.

Omo, Queen of Vesuva

The Lost Caverns of Ixalan Commander

Clavileño, First of the Blessed

Vampire Demon

Legendary Creature — Vampire Cleric

Whenever you attack, target attacking Vampire that isn't a Demon becomes a Demon in addition to its other types. It gains "When this creature dies, draw a card and create a tapped 4/3 white and black Vampire Demon creature token with flying."

The Lost Caverns of Ixalan Art Series

Secret Lair Drop

Legendary Creature — Merfolk Shaman

Tap another untapped Merfolk you control: Kumena can't be blocked this turn.
Tap three untapped Merfolk you control: Draw a card.
Tap five untapped Merfolk you control: Put a +1/+1 counter on each Merfolk you control.