edhseer Commander synergy, explained
Instant
Mana cost: {3}{U}{U}
Counter target spell. Search its controller's graveyard, hand, and library for all cards with the same name as that spell and exile them. Then that player shuffles.
on-cast —
on-cast — searches a library
on-cast —
Causes: counter a spell, search spell , shuffle a library.
Cares about: nothing.
a library is searched — 982 cards in the game can cause this (Counterbore is one).
When a spell searches a library thanks to Counterbore:
an instant is cast — 3,931 cards in the game can cause this (Counterbore is one).
When Counterbore 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 (Counterbore is one).
When Counterbore is cast:
5 other cards care about it too. These are the ones with the most connections.