edhseer Commander synergy, explained
Land — Island Swamp
({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.
static —
Causes: nothing.
Cares about: nothing.
a Swamp enters the battlefield — 63 cards in the game can cause this (Sunken Hollow is one).
When Sunken Hollow enters:
an Island enters the battlefield — 64 cards in the game can cause this (Sunken Hollow is one).
a land enters the battlefield — 1,560 cards in the game can cause this (Sunken Hollow is one).
When Sunken Hollow enters:
199 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 (Sunken Hollow is one).
17 other cards care about it too. These are the ones with the most connections.