edhseer Commander synergy, explained
Instant
Mana cost: {2}{G}
Choose a creature type. Look at the top six cards of your library. You may reveal any number of cards of the chosen type from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.
on-cast — searches a library
Flashback {3}{G}
Causes: nothing.
Cares about: nothing.
an instant is cast — 3,931 cards in the game can cause this (For the Ancestors is one).
When For the Ancestors is cast:
427 other cards care about it too. These are the ones with the most connections.
anything is cast — 31,128 cards in the game can cause this (For the Ancestors is one).
When For the Ancestors is cast:
5 other cards care about it too. These are the ones with the most connections.