Bayou

a Swamp enters the battlefield — 63 cards in the game can cause this (Bayou is one).

1. Thelon's Chant — When Bayou enters, Thelon's Chant deals 3 damage
2. Veilborn Ghoul — When Bayou enters, Veilborn Ghoul returns itself from the graveyard
3. Staff of the Death Magus — When Bayou enters, Staff of the Death Magus gains you 1 life
4. Dread Presence — When Bayou enters, Dread Presence triggers

a Forest enters the battlefield — 85 cards in the game can cause this (Bayou is one).

1. Titania, Nature's Force — When Bayou enters, Titania, Nature's Force makes a token
2. Baru, Fist of Krosa — When Bayou enters, Baru, Fist of Krosa gives +1/+1
3. Reach of Branches — When Bayou enters, Reach of Branches returns itself from the graveyard
4. Tourach's Chant — When Bayou enters, Tourach's Chant deals 3 damage
5. Battlewand Oak — When Bayou enters, Battlewand Oak gets +2/+2
6. Staff of the Wild Magus — When Bayou enters, Staff of the Wild Magus gains you 1 life
7. Necklace of Girion — When Bayou enters, Necklace of Girion puts a counter on a creature
8. Roiling Canopy — When Bayou enters, Roiling Canopy gives +3/+3

a land enters the battlefield — 1,542 cards in the game can cause this (Bayou is one).

1. Primeval Bounty — When Bayou enters, Primeval Bounty gains you 3 life
2. Dancing from Dark to Dawn — When Bayou enters, Dancing from Dark to Dawn makes a token
3. Toph, Earthbending Master — When Bayou enters, Toph, Earthbending Master puts a counter on a permanent
4. Emeria Shepherd — When Bayou enters, Emeria Shepherd brings a card back
5. Quest for the Necropolis — When Bayou enters, Quest for the Necropolis puts a quest counter on itself
6. Soul Stair Expedition — When Bayou enters, Soul Stair Expedition puts a quest counter on itself
7. Nissa of Shadowed Boughs — When Bayou enters, Nissa of Shadowed Boughs puts counters on a permanent
8. Thranduil, Sindarin Liege // Silvan Rally — When Bayou enters, Thranduil, Sindarin Liege // Silvan Rally makes a token
9. Silvan Reveler — When Bayou enters, Silvan Reveler returns itself from the graveyard
10. Floral Evoker — When Bayou enters, Floral Evoker puts a +1/+1 counter on itself

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

anything enters the battlefield — 26,290 cards in the game can cause this (Bayou is one).

1. Nature's Wrath — When Bayou enters, Nature's Wrath makes a player sacrifice a Swamp or permanent

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