Doorman

a Mutant attacks — 280 cards in the game can cause this (Doorman is one).

1. Wolverine, Claws Out — When Doorman attacks, Wolverine, Claws Out makes your creatures bigger

a Mutant deals combat damage — 280 cards in the game can cause this (Doorman is one).

1. Heroes in a Half Shell — When Doorman deals combat damage, Heroes in a Half Shell puts a counter on a permanent

a Mutant enters the battlefield — 286 cards in the game can cause this (Doorman is one).

1. Genghis Frog — When Doorman enters, Genghis Frog makes a token
2. X-23, Deadly Weapon — When Doorman enters, X-23, Deadly Weapon puts a counter on a permanent
3. April O'Neil, Live on the Scene — When Doorman enters, April O'Neil, Live on the Scene triggers

a nontoken Hero enters the battlefield — 358 cards in the game can cause this (Doorman is one).

1. Black Panther, Vanguard — When Doorman enters, Black Panther, Vanguard triggers

a Hero enters the battlefield — 375 cards in the game can cause this (Doorman is one).

1. Hawkeye, Trick Shot — When Doorman enters, Hawkeye, Trick Shot deals damage
2. Captain America, Team Leader — When Doorman enters, Captain America, Team Leader grants haste and vigilance
3. Nighthawk, Dark Defender — When Doorman enters, Nighthawk, Dark Defender gives +1/+1
4. Team Transmitter — When Doorman enters, Team Transmitter gains you 1 life

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

When Doorman 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

111 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 (Doorman is one).

When Doorman 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

180 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 (Doorman is one).

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

18 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 (Doorman is one).

When Doorman attacks:

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

a creature deals combat damage — 17,934 cards in the game can cause this (Doorman is one).

When Doorman deals combat damage:

1. Locutus of Borg — makes a token
2. Antagonist Incorporator — makes a token
3. Hive Mind Coprocessor — makes you lose life

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

a creature is cast — 18,010 cards in the game can cause this (Doorman is one).

When Doorman is cast:

1. Primeval Bounty — makes a token
2. Bloodbond March — brings a card back
3. Dancing from Dark to Dawn — puts that spell's mana value counters on a creature
4. Endrek Sahr, Master Breeder — makes that spell's mana value tokens
5. Summon: Fenrir — it arrives with counters thanks to Summon: Fenrir

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

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

1. Slash, Reptile Rampager — When Doorman enters, Slash, Reptile Rampager deals 2 damage
2. Gimli of the Glittering Caves — When Doorman enters, Gimli of the Glittering Caves puts counters on a permanent
3. Ray Fillet, Wave Warrior — When Doorman enters, Ray Fillet, Wave Warrior puts a counter on itself
4. Legolas Greenleaf — When Doorman enters, Legolas Greenleaf puts a counter on a permanent
5. The Neutrinos — When Doorman enters, The Neutrinos gets +1/+0
6. Wingnut, Bat on the Belfry — When Doorman enters, Wingnut, Bat on the Belfry grants flying, haste and menace
7. Aetherstorm Roc — When Doorman enters, Aetherstorm Roc puts a counter on a permanent you control
8. Raphael, Most Attitude — When Doorman enters, Raphael, Most Attitude exiles a card from your library

297 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 (Doorman is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Doorman enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself

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