edhseer Commander synergy, explained
Land — Cave
You may have this land enter tapped as a copy of any land card in a graveyard, except it's a Cave in addition to its other types.
static — copies a permanent
static — changes what something is
Add {C}.
activated {T} — adds 1 mana
Causes: copy a land.
Cares about: nothing.
a Cave enters the battlefield — 18 cards in the game can cause this (Echoing Deeps is one).
a Cave it grants abilities to — 21 cards in the game can cause this.
20 other cards cause it too. These are the ones with the most connections.
a land enters the battlefield — 1,560 cards in the game can cause this (Echoing Deeps is one).
When Echoing Deeps enters:
199 other cards care about it too. These are the ones with the most connections.