edhseer Commander synergy, explained
Land
Add {C}.
activated {T} — adds 1 mana
Roll a d10. Put target artifact, creature, or planeswalker into its owner's library just beneath the top X cards of that library, where X is the result. Activate only as a sorcery.
activated {5}, {T}, Exile this land —
activated {5}, {T}, Exile this land —
activated {5}, {T}, Exile this land —
Causes: exile a land, a land leaves the battlefield, roll a die, an artifact leaves the battlefield, a creature leaves the battlefield, a planeswalker leaves the battlefield.
Cares about: nothing.
a die is rolled — 88 cards in the game can cause this (Underdark Rift is one).
When Underdark Rift rolls a die:
a land enters the battlefield — 1,560 cards in the game can cause this (Underdark Rift is one).
When Underdark Rift enters:
199 other cards care about it too. These are the ones with the most connections.
anything is exiled — 2,497 cards in the game can cause this (Underdark Rift is one).
a nontoken creature leaves the battlefield — 4,133 cards in the game can cause this (Underdark Rift is one).
3 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 (Underdark Rift is one).
When a creature leaves the battlefield thanks to Underdark Rift:
26 other cards care about it too. These are the ones with the most connections.