Hag Eye
A hag coven can craft a magic item called a hag eye, which is made from a real eye coated in varnish and often fitted to a pendant or other wearable item. The hag eye is usually entrusted to a minion for safekeeping and transport. A hag in the coven can take an action to see what the hag eye sees if the hag eye is on the same plane of existence.
(MM 176)