Avatar: The Last Airbender

Instant — Lesson

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Octopus Form

Marvel's Spider-Man Promos

Legendary Creature — Human Scientist Villain

Whenever you draw your first or second card each turn, put an ingenuity counter on Lady Octopus.
{T}: You may cast an artifact spell from your hand with mana value less than or equal to the number of ingenuity counters on Lady Octopus without paying its mana cost.

Lady Octopus, Inspired Inventor

Card

Doctor Octopus, Master Planner

Marvel's Spider-Man Art Series

Other Villains you control get +2/+2.
Your maximum hand size is eight.
At the beginning of your end step, if you have fewer than eight cards in hand, draw cards equal to the difference.

Final Fantasy

Legendary Creature — Octopus

Whenever you cast a noncreature spell, if at least four mana was spent to cast it, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a noncreature spell, if at least eight mana was spent to cast it, put eight +1/+1 counters on Ultros.

Ultros, Obnoxious Octopus

Bloomburrow Commander Tokens

Kiora, Master of the Depths

Octomancer

Fisher's Talent

Crush of Tentacles

Token Creature — Octopus

Octopus

Unknown Event

Legendary Creature — Octopus Insect

Hexproof
When The Octopus Official enters, if you didn't have an active tournament, announce the top 8. (Reveal cards from your library until you reveal eight nonland cards. Randomly distribute them into four two-card piles, like a tournament bracket. Put land cards on the bottom in a random order.)
At the beginning of your upkeep, randomly put a card from each pile into your hand. The other cards advance to the next round. If only one card remains, you may cast it without paying its mana cost four times.

The Octopus Official

Kamigawa: Neon Dynasty

Artifact Creature — Equipment Octopus

Whenever this creature or equipped creature deals combat damage to a player, draw a card.
Reconfigure {2} ({2}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Acquisition Octopus

The List

Enchantment — Aura

Enchant creature
Enchanted creature has base power and toughness 8/8 and has "Whenever this creature attacks, you may tap target creature with power 8 or less."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Octopus Umbra

Ikoria: Lair of Behemoths Promos

Creature — Octopus

Mutate {1}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Sea-Dasher Octopus

Unstable

Host Creature — Octopus Rigger

When this creature enters, this creature assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Crafty Octopus

Journey into Nyx

This creature can't attack unless defending player controls an enchantment or an enchanted permanent.