Octomancer

a Frog attacks — 135 cards in the game can cause this (Octomancer is one).

1. Grolnok, the Omnivore — When Octomancer attacks, Grolnok, the Omnivore mills a card

a Frog enters the battlefield — 140 cards in the game can cause this (Octomancer is one).

1. Valley Mightcaller — When Octomancer enters, Valley Mightcaller puts a +1/+1 counter on itself

provide a creature to sacrifice — 2,720 cards in the game can cause this.

1. Jalira, Master Polymorphist — Octomancer makes fodder for Jalira, Master Polymorphist
2. Polymorph — Octomancer makes fodder for Polymorph
3. Birthing Ritual — Octomancer makes fodder for Birthing Ritual
4. Proteus Staff — Octomancer makes fodder for Proteus Staff
5. Synthetic Destiny — Octomancer makes fodder for Synthetic Destiny
6. Mass Polymorph — Octomancer makes fodder for Mass Polymorph

2,714 other cards cause it too. These are the ones with the most connections.

a creature token enters the battlefield — 2,799 cards in the game can cause this (Octomancer is one).

When a creature enters thanks to Octomancer:

1. Securitron Squadron — puts a counter on a permanent
2. Anointer Priest — gains you 1 life
3. Nesting Dovehawk — puts a +1/+1 counter on itself

a creature token is created — 2,799 cards in the game can cause this (Octomancer is one).

1. Staff of the Storyteller — When Octomancer makes a creature token, Staff of the Storyteller puts a story counter on itself

3 other cards care about it too. These are the ones with the most connections.

a token enters the battlefield — 3,710 cards in the game can cause this (Octomancer is one).

When a creature enters thanks to Octomancer:

1. Baron Bertram Graywater — makes a token
2. Marneus Calgar — draws you 1 card
3. Belladonna Took — gains you 1 life
4. Kambal, Profiteering Mayor — makes each opponent lose 1 life
5. Lucy MacLean, Positively Armed — makes a token
6. Mister Fantastic, Reed Richards — draws you 1 card
7. Cloakwood Swarmkeeper — puts a +1/+1 counter on itself
8. Woodland Champion — puts that many +1/+1 counters on itself
9. Leonardo, the Balance — puts a counter on a creature
10. Spiritcall Enthusiast // Scrollboost — becomes prepared

3 other cards care about it too. These are the ones with the most connections.

a token is created — 3,711 cards in the game can cause this (Octomancer is one).

When Octomancer makes a creature token:

1. Akim, the Soaring Wind — makes a token
2. Idol of Oblivion — draws you 1 card
3. Rosie Cotton of South Lane — puts a counter on a permanent
4. Mirkwood Bats — makes each opponent lose 1 life

17 other cards care about it too. These are the ones with the most connections.

anything attacks — 17,934 cards in the game can cause this (Octomancer is one).

When Octomancer attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Grim Javelineer — gives +1/+0
4. Invisible Woman — triggers
5. Caesar, Legion's Emperor — sacrifices a creature
6. Guide of Souls — triggers
7. Campsite Cuisine — sacrifices a Food
8. Gossip's Talent — triggers
9. Banon, the Returners' Leader — draws and discards
10. Toph, Earthbending Master — puts a counter on a permanent

122 other cards care about it too. These are the ones with the most connections.

a creature attacks — 17,934 cards in the game can cause this (Octomancer is one).

When Octomancer attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Invasion of New Capenna // Holy Frazzle-Cannon — puts counters on a permanent
5. Chorale of the Void — brings a card back
6. Anim Pakal, Thousandth Moon — puts a +1/+1 counter on itself
7. Saw — sacrifices a creature
8. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
9. Ultima Weapon — kills a creature an opponent controls
10. Total War — kills a creature

194 other cards care about it too. These are the ones with the most connections.

a creature blocks — 17,934 cards in the game can cause this (Octomancer is one).

When Octomancer blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Carnage Gladiator — makes a player lose 1 life
3. Barrow-Blade — strips abilities
4. Heat of Battle — deals 1 damage
5. Battle Strain — deals 1 damage
6. Favor of the Woods — gains you 3 life
7. Tide of War — sacrifices a creature
8. Dead-Iron Sledge — kills a creature
9. Dwindle — kills a creature
10. Shield of the Righteous — triggers

20 other cards care about it too. These are the ones with the most connections.

a nontoken creature attacks — 17,934 cards in the game can cause this (Octomancer is one).

When Octomancer attacks:

1. Mardu Ascendancy — makes a token
2. Basri Ket — makes a token
3. Militia's Pride — makes a token

a creature enters the battlefield — 19,800 cards in the game can cause this (Octomancer is one).

1. Slash, Reptile Rampager — When a creature enters thanks to Octomancer, Slash, Reptile Rampager deals 2 damage
2. Ray Fillet, Wave Warrior — When Octomancer enters, Ray Fillet, Wave Warrior puts a counter on itself
3. The Neutrinos — When a creature enters thanks to Octomancer, The Neutrinos gets +1/+0
4. Wingnut, Bat on the Belfry — When a creature enters thanks to Octomancer, Wingnut, Bat on the Belfry grants flying, haste and menace
5. Aetherstorm Roc — When a creature enters thanks to Octomancer, Aetherstorm Roc puts a counter on a permanent you control
6. Raphael, Most Attitude — When a creature enters thanks to Octomancer, Raphael, Most Attitude exiles a card from your library

333 other cards care about it too. These are the ones with the most connections.

anything enters the battlefield — 26,499 cards in the game can cause this (Octomancer is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When a creature enters thanks to Octomancer, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

51 other cards care about it too. These are the ones with the most connections.