edhseer Commander synergy, explained
Land
This land enters tapped. As it enters, choose a color.
Add one mana of the chosen color.
activated {T} — adds 1 mana
For each color among monocolored permanents you control, add one mana of that color.
activated {1}, {T} — adds mana
Causes: nothing.
Cares about: nothing.
a land enters the battlefield — 1,560 cards in the game can cause this (Tarnation Vista is one).
When Tarnation Vista enters:
199 other cards care about it too. These are the ones with the most connections.