Karlach, Fury of Avernus

a creature untaps — 155 cards in Karlach's colors can cause this (Karlach is one).

1. Fishing Pole — When a creature untaps thanks to Karlach, Fury of Avernus, Fishing Pole triggers

a creature attacks — 3,451 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus attacks:

1. Adaptive Omnitool — searches a library
2. Staff of Titania — makes a token
3. Inquisitorial Rosette — makes a token
4. Andúril, Flame of the West — makes 2 tokens
5. Saw — sacrifices a creature
6. Ultima Weapon — kills a creature an opponent controls
7. Total War — kills a creature
8. The Spear of Leonidas — triggers
9. Norin the Wary — flickers itself
10. Throwing Knife — sacrifices itself

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

a creature blocks — 3,451 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus blocks:

1. Barrow-Blade — strips abilities
2. Heat of Battle — deals 1 damage
3. Battle Strain — deals 1 damage
4. Tide of War — sacrifices a creature
5. Dead-Iron Sledge — kills a creature

1 other card cares about it too. These are the ones with the most connections.

anything attacks — 3,451 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus attacks:

1. ED-E, Lonesome Eyebot — puts a quest counter on itself
2. Misty Mountains Raider — puts 2 counters on a Goblin or Army
3. Razorkin Hordecaller — makes a token
4. War Effort — makes a token
5. Inti, Seneschal of the Sun — triggers
6. Gut, True Soul Zealot — sacrifices a creature or artifact
7. Cool but Rude — draws and discards
8. Swashbuckler Extraordinaire — sacrifices a Treasure
9. Puppet Master, String Puller — triggers
10. Phyrexian Ironworks — puts a counter on a permanent you control

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

a creature is cast — 3,468 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus is cast:

1. Summon: Brynhildr — grants haste
2. Oketra's Monument — makes a token
3. Screamer-Killer — deals 5 damage
4. Bontu's Monument — makes each opponent lose 1 life
5. Vanquisher's Banner — draws you 1 card
6. Sarkhan's Unsealing — deals 4 damage
7. Rhonas's Monument — gives +2/+2
8. Kumano Faces Kakkazan // Etching of Kumano — it arrives with counters thanks to Kumano Faces Kakkazan // Etching of Kumano
9. Hazoret's Monument — draws and discards
10. Kefnet's Monument — triggers

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

a nontoken creature enters the battlefield — 3,511 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus enters:

1. Minion Reflector — makes a token
2. Molten Echoes — makes a token
3. Flameshadow Conjuring — makes a token
4. Mirror March — flips a coin

a creature enters the battlefield — 3,801 cards in Karlach's colors can cause this (Karlach is one).

When Karlach, Fury of Avernus enters:

1. Slash, Reptile Rampager — deals 2 damage
2. Gimli of the Glittering Caves — puts counters on a permanent
3. Wingnut, Bat on the Belfry — grants flying, haste and menace
4. Blasting Station — untaps itself
5. General Kreat, the Boltbringer — deals 1 damage
6. Bloodline Pretender — puts a +1/+1 counter on itself
7. Raphael, Most Attitude — exiles a card from your library
8. Mogg Bombers — sacrifices itself
9. Flame-Kin War Scout — sacrifices itself
10. Monkey Cage — sacrifices itself

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