edhseer Commander synergy, explained
Land
Hideaway 4
This land enters tapped.
Add {W}.
activated {T} — adds 1 mana
You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.
Causes: nothing.
Cares about: nothing.
a land enters the battlefield — 1,560 cards in the game can cause this (Windbrisk Heights is one).
When Windbrisk Heights enters:
199 other cards care about it too. These are the ones with the most connections.