edhseer Commander synergy, explained
Land
This land enters tapped unless you control a Plains.
Add {W}.
activated {T} — adds 1 mana
Look at the top five cards of your library. You may reveal a historic card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
activated {2}{W}{W}, {T} — searches a library
Causes: nothing.
Cares about: nothing.
a land enters the battlefield — 1,560 cards in the game can cause this (Monumental Henge is one).
When Monumental Henge enters:
199 other cards care about it too. These are the ones with the most connections.