Polymorph

anything leaves the battlefield — 1 card in the game can cause this (Polymorph is one).

1. Electro, Assaulting Battery — When Electro, Assaulting Battery leaves the battlefield thanks to Polymorph, it triggers
2. Chainer, Dementia Master — When Chainer, Dementia Master leaves the battlefield thanks to Polymorph, it exiles a Nightmare

hits creature — 2,298 cards in the game can cause this.

1. Kapsho Kitefins — Polymorph can put Kapsho Kitefins onto the battlefield from your library
2. Sharding Sphinx — Polymorph can put Sharding Sphinx onto the battlefield from your library
3. Madame Web, Clairvoyant — Polymorph can put Madame Web, Clairvoyant onto the battlefield from your library
4. Shadow Puppeteers — Polymorph can put Shadow Puppeteers onto the battlefield from your library
5. Screaming Swarm — Polymorph can put Screaming Swarm onto the battlefield from your library
6. Ultimecia, Temporal Threat — Polymorph can put Ultimecia, Temporal Threat onto the battlefield from your library
7. Deepfathom Skulker — Polymorph can put Deepfathom Skulker onto the battlefield from your library
8. Starwinder — Polymorph can put Starwinder onto the battlefield from your library
9. Windreader Sphinx — Polymorph can put Windreader Sphinx onto the battlefield from your library
10. Twins of Discord — Polymorph can put Twins of Discord onto the battlefield from your library

2,288 other cards cause it too. These are the ones with the most connections.

a library is shuffled — 1,189 cards in the game can cause this (Polymorph is one).

When Polymorph shuffles a library:

1. Cosi's Trickster — puts a +1/+1 counter on itself
2. Psychic Surgery — triggers

a creature to sacrifice — 2,720 cards in the game can cause this (Polymorph is one).

1. Primeval Bounty — Primeval Bounty makes fodder for Polymorph
2. Saheeli, Radiant Creator — Saheeli, Radiant Creator makes fodder for Polymorph
3. Captain Jean-Luc Picard — Captain Jean-Luc Picard makes fodder for Polymorph
4. Invisible Woman — Invisible Woman makes fodder for Polymorph

2,716 other cards care about it too. These are the ones with the most connections.

a creature in a graveyard — 2,769 cards in the game can cause this (Polymorph is one).

Polymorph puts cards into the graveyard that:

1. Havengul Lich — can bring back
2. Liliana the Repentant — can bring back
3. Paleoloth — can bring back
4. Chainer, Nightmare Adept — can bring back
5. Banon, the Returners' Leader — can bring back
6. Surgical Suite // Hospital Room — can bring back
7. Sword of Light and Shadow — can bring back
8. Necromantic Thirst — can bring back
9. Krile Baldesion — can bring back
10. Extus, Oriq Overlord // Awaken the Blood Avatar — can bring back

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

a nontoken creature dies — 2,769 cards in the game can cause this (Polymorph is one).

When a creature dies thanks to Polymorph:

1. Zahur, Glory's Past — makes a token
2. Liesa, Forgotten Archangel — brings a card back
3. Avacyn, Angel of Horror — brings a card back
4. Yedora, Grave Gardener — brings a card back
5. Nim Deathmantle — brings a card back
6. Valkyrie's Call — brings a card back
7. Decaying Soil — brings a card back
8. High-Society Hunter — draws you 1 card
9. Liliana, Heretical Healer // Liliana, Defiant Necromancer — flickers itself
10. Body Launderer — draws and discards

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

a creature dies — 2,830 cards in the game can cause this (Polymorph is one).

1. Pious Evangel // Wayward Disciple — When a creature dies thanks to Polymorph, Pious Evangel // Wayward Disciple makes each opponent lose 1 life
2. Daxos, Blessed by the Sun — When a creature dies thanks to Polymorph, Daxos, Blessed by the Sun gains you 1 life
3. Elas il-Kor, Sadistic Pilgrim — When a creature dies thanks to Polymorph, Elas il-Kor, Sadistic Pilgrim makes each opponent lose 1 life
4. Shriveling Rot — When a creature dies thanks to Polymorph, Shriveling Rot makes a player lose life equal to its toughness
5. Boss's Chauffeur — When Boss's Chauffeur dies thanks to Polymorph, it makes a token
6. Jeskai Sage — When Jeskai Sage dies thanks to Polymorph, it draws you 1 card
7. Dinosaur Egg — When Dinosaur Egg dies thanks to Polymorph, it triggers
8. Cyclops Superconductor — When Cyclops Superconductor dies thanks to Polymorph, it triggers
9. Saffi Eriksdotter — When a creature dies thanks to Polymorph, Saffi Eriksdotter sacrifices itself
10. Treacherous Vampire — When Treacherous Vampire dies thanks to Polymorph, it makes you lose life

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

a creature leaves the battlefield — 4,238 cards in the game can cause this (Polymorph is one).

1. Ninja Teen — When a creature leaves the battlefield thanks to Polymorph, Ninja Teen makes each opponent lose 1 life

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

a permanent is put into a graveyard from the battlefield — 5,057 cards in the game can cause this (Polymorph is one).

1. Gerrard, Weatherlight Hero — When Gerrard, Weatherlight Hero dies thanks to Polymorph, it exiles itself

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

a card in a graveyard — 7,589 cards in the game can cause this (Polymorph is one).

1. Havi, the All-Father — Polymorph fills your graveyard toward the 4 or more cards Havi, the All-Father needs
2. Repentant Vampire — Polymorph fills your graveyard toward the 7 or more cards Repentant Vampire needs
3. Athreos, Shroud-Veiled — Polymorph puts cards into the graveyard that Athreos, Shroud-Veiled can bring back

441 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 (Polymorph is one).

1. Odunos River Trawler — When Odunos River Trawler enters thanks to Polymorph, it brings a card back
2. Technomancer — When Technomancer enters thanks to Polymorph, it mills a card
3. Sludge Titan — When Sludge Titan enters thanks to Polymorph, it mills a card
4. Moriok Scavenger — When Moriok Scavenger enters thanks to Polymorph, it brings a card back
5. Corpse Cur — When Corpse Cur enters thanks to Polymorph, it brings a card back
6. Rayblade Trooper — When Rayblade Trooper enters thanks to Polymorph, it puts a counter on a creature
7. Puppeteer Clique — When Puppeteer Clique enters thanks to Polymorph, it brings a card back
8. Crypt Angel — When Crypt Angel enters thanks to Polymorph, it brings a card back
9. Enslaved Horror — When Enslaved Horror enters thanks to Polymorph, it brings a card back
10. Overseer of the Damned — When Overseer of the Damned enters thanks to Polymorph, it kills a creature an opponent controls

438 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 (Polymorph is one).

1. The Master, Transcendent — When The Master, Transcendent enters thanks to Polymorph, it puts 2 counters on a permanent
2. Borg Queen, Perfection Manifest — When Borg Queen, Perfection Manifest enters thanks to Polymorph, it brings a card back
3. Alharu, Solemn Ritualist — When Alharu, Solemn Ritualist enters thanks to Polymorph, it puts a counter on a creature
4. Garna, the Bloodflame — When Garna, the Bloodflame enters thanks to Polymorph, it brings a card back
5. Ruxa, Patient Professor — When Ruxa, Patient Professor enters thanks to Polymorph, it brings a card back
6. The Reaper, King No More — When The Reaper, King No More enters thanks to Polymorph, it puts a counter on a creature
7. Vastlands Scavenger // Bind to Life — When Vastlands Scavenger // Bind to Life enters thanks to Polymorph, it becomes prepared

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