Hourglass

Thre are two Hourglasses which fall under this category:

Hourglass of Nicodemus
The Hourglass of Nicodemus is a strong magical device. With it, it is possible to walk through time traps without any harm. Also, with it it is possible to talk with the Time Lord over any kind of distance without problem.

Because of his madness through the Tetheradon Generator, Nicodemus was unable to hold the enchantment on the Hourglass, and sold it. The Avatar aquired it in Ultima VII, and after destroying the Tetheradon Generator, asked Nicodemus to re-enchant the Hourglass. With it, it was easy to breach the trap in front of the Sphere Generator and talk to the Time Lord after the Moongates had collapsed.

Hourglass of Fate
Thoxa gave it to the Avatar right at the beginning of Ultima VII/2. The Hourglass of Fate not only enables the monks to return him/her to life after bein mortally wounded, but also was used by the Avatar to call a monk, if a companion had died.