River Song

surveil — 233 cards in the game can cause this.

1. Diviner of Victory // Unwind History — When Diviner of Victory // Unwind History surveils, River Song puts a +1/+1 counter on itself

232 other cards cause it too. These are the ones with the most connections.

a Human gets a counter — 326 cards in the game can cause this (River Song is one).

1. Cloaked Cadet — When River Song gets a counter, Cloaked Cadet draws you 1 card

scry — 420 cards in the game can cause this.

1. Zaffai, Thunder Conductor — When Zaffai, Thunder Conductor scries, River Song puts a +1/+1 counter on itself
2. Eager Construct — When Eager Construct scries, River Song puts a +1/+1 counter on itself
3. Myr Custodian — When a permanent scries thanks to Myr Custodian, River Song puts a +1/+1 counter on itself
4. Kozilek's Command — When Kozilek's Command scries, River Song puts a +1/+1 counter on itself
5. Ingenious Mastery — When Ingenious Mastery scries, River Song puts a +1/+1 counter on itself
6. Model of Unity — When Model of Unity scries, River Song puts a +1/+1 counter on itself

414 other cards cause it too. These are the ones with the most connections.

a Rogue attacks — 636 cards in the game can cause this (River Song is one).

1. Soaring Thought-Thief — When River Song attacks, Soaring Thought-Thief mills a card

a Rogue deals combat damage — 636 cards in the game can cause this (River Song is one).

1. Anowon, the Ruin Thief — When River Song deals combat damage, Anowon, the Ruin Thief mills a card

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

a Rogue creature enters the battlefield — 657 cards in the game can cause this (River Song is one).

1. Cloak and Dagger — When River Song enters, Cloak and Dagger triggers

a Rogue enters the battlefield — 659 cards in the game can cause this (River Song is one).

1. Thieves' Guild Enforcer — When River Song enters, Thieves' Guild Enforcer mills a card

search your library — 982 cards in the game can cause this.

1. Jace, Architect of Thought — When a creature, artifact, enchantment, instant, sorcery, planeswalker or battle searches a library thanks to Jace, Architect of Thought, River Song puts a +1/+1 counter on itself
2. Arcum Dagsson — When an artifact searches a library thanks to Arcum Dagsson, River Song puts a +1/+1 counter on itself
3. Krenko's Buzzcrusher — When a land searches a library thanks to Krenko's Buzzcrusher, River Song puts a +1/+1 counter on itself
4. Magmatic Hellkite — When a land searches a library thanks to Magmatic Hellkite, River Song puts a +1/+1 counter on itself
5. Sandworm — When a land searches a library thanks to Sandworm, River Song puts a +1/+1 counter on itself
6. Grinning Totem — When a permanent searches a library thanks to Grinning Totem, River Song puts a +1/+1 counter on itself
7. Jester's Cap — When a permanent searches a library thanks to Jester's Cap, River Song puts a +1/+1 counter on itself
8. Jester's Mask — When a permanent searches a library thanks to Jester's Mask, River Song puts a +1/+1 counter on itself
9. Price of Freedom — When a land searches a library thanks to Price of Freedom, River Song puts a +1/+1 counter on itself
10. Sundering Eruption // Volcanic Fissure — When a land searches a library thanks to Sundering Eruption // Volcanic Fissure, River Song puts a +1/+1 counter on itself

972 other cards cause it too. These are the ones with the most connections.

a creature gets a counter — 2,691 cards in the game can cause this (River Song is one).

When River Song gets a counter:

1. Hollowmurk Siege — draws you 1 card
2. Ant-Man, Colony Commander — makes a token
3. Earth Kingdom General — gains you that much life
4. Casey Jones, Back Alley Brute — deals that much damage
5. Generous Patron — draws you 1 card
6. Shalai and Hallar — deals that much damage
7. Danny Pink — draws you 1 card
8. Enduring Scalelord — puts a +1/+1 counter on itself
9. Bold Plagiarist — puts counters on a permanent
10. Mikey & Leo, Chaos & Order — draws you 1 card

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

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

When River Song deals noncombat damage:

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

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

life is lost — 3,160 cards in the game can cause this (River Song is one).

When River Song makes a player lose life:

1. Far Fortune, End Boss — raises your speed
2. Zahur, Glory's Past — raises your speed
3. Mendicant Core, Guidelight — raises your speed
4. Aether Syphon — raises your speed
5. Vnwxt, Verbose Host — raises your speed
6. Embalmed Ascendant — raises your speed
7. Slick Imitator — raises your speed
8. Nesting Bot — raises your speed
9. Howlsquad Heavy — raises your speed
10. Hour of Victory — raises your speed

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

a card is drawn — 3,815 cards in the game can cause this (River Song is one).

When River Song makes a player draw a card:

1. Temmet, Naktamun's Will — gives +1/+1
2. Niv-Mizzet, Parun — deals 1 damage
3. The Locust God — makes a token
4. Starving Revenant — makes each opponent lose 1 life
5. Diviner's Wand — gets +1/+1
6. Ominous Seas — puts a foreshadow counter on itself
7. Dream Trawler — gets +1/+0
8. Iron Man, Armored Avenger — puts a counter on a creature
9. The Astonishing Ant-Man — puts a +1/+1 counter on itself
10. Psychosis Crawler — makes each opponent lose 1 life

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

anything gets a counter — 4,415 cards in the game can cause this (River Song is one).

1. All Will Be One — When River Song gets a counter, All Will Be One deals that much damage

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

a Human enters the battlefield — 4,639 cards in the game can cause this (River Song is one).

When River Song enters:

1. General Kudro of Drannith — hits a graveyard
2. Heronblade Elite — puts a +1/+1 counter on itself
3. Kyler, Sigardian Emissary — puts a +1/+1 counter on itself
4. Thalia's Lieutenant — puts a +1/+1 counter on itself
5. Champion of the Parish — puts a +1/+1 counter on itself
6. Captain of the Mists — untaps itself
7. Erkenbrand, Lord of Westfold — gives +1/+0
8. Beregond of the Guard — gives +1/+1
9. Théoden, King of Rohan — grants double strike
10. Lossarnach Captain — taps a creature an opponent controls

2 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 (River Song is one).

1. Anthem of Rakdos — When River Song attacks, Anthem of Rakdos gives +2/+0

192 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 (River Song is one).

1. Invisible Woman — When River Song attacks, Invisible Woman triggers

126 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 (River Song is one).

When River Song enters:

1. Scurry Oak — puts a counter on itself
2. Fathom Mage — puts a counter on itself
3. Lonis, Genetics Expert — puts a counter on itself

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