Outnumber

anything deals noncombat damage — 3,068 cards in the game can cause this (Outnumber is one).

When Outnumber deals noncombat damage:

1. Quest for Pure Flame — puts a quest counter on itself
2. Soul-Scar Mage — puts that many counters on a permanent
3. Fear of Burning Alive — deals that amount damage
4. Niv-Mizzet, Visionary — draws you that many cards
5. Chandra's Incinerator — deals that much damage
6. Chandra's Pyreling — gets +1/+0
7. Talon of Pain — puts a charge counter on itself
8. Asgardian Inspiration — returns itself from the graveyard
9. Thor, Guardian of Midgard — exiles a card from your library
10. Virtue of Courage // Embereth Blaze — exiles a card from your library

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

an instant is cast — 3,931 cards in the game can cause this (Outnumber is one).

When Outnumber is cast:

1. Tomik, Izzet Sparkmage — gets +1/+1
2. Tor Wauki the Younger — deals 2 damage
3. Lunar Mystic — draws you 1 card
4. Ojer Pakpatiq, Deepest Epoch // Temple of Cyclical Time — grants rebound
5. Repeated Reverberation — copies an ability
6. Riku of Two Reflections — copies a spell
7. Sword of Wealth and Power — copies a spell
8. Lilah, Undefeated Slickshot — gets +1/+1
9. Artist's Talent — draws and discards
10. In the Eye of Chaos — counters a spell

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

a creature is dealt damage — 18,923 cards in the game can cause this (Outnumber is one).

When a creature is dealt damage thanks to Outnumber:

1. Soul Link — gains you that much life
2. Shriveling Rot — kills it
3. Cryoshatter — kills a creature
4. Hot Soup — kills a creature
5. Cracked Skull — kills a creature
6. Sporogenic Infection — kills a creature
7. Frozen Solid — kills a creature
8. Mortal Wound — kills a creature
9. Mire Blight — kills it
10. Death Pits of Rath — kills it

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

anything is cast — 31,128 cards in the game can cause this (Outnumber is one).

When Outnumber is cast:

1. Windrider Wizard — draws you 1 card
2. Relic Amulet — puts a charge counter on itself
3. Rockslide Sorcerer — deals 1 damage
4. Umara Wizard // Umara Skyfalls — grants flying
5. Alania, Divergent Storm — makes an opponent draw 1 card
6. Umara Mystic — gets +2/+0
7. Master of Winds — triggers

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