Scroll of Resurrection (Warcraft III)

The Scroll of Resurrection brings 6 of your dead units back to life.

Source
Thrall can find one in The Oracle, chapter 7 of the Warcraft III orc campaign, The Invasion of Kalimdor.

Kael, Lady Vashj and Illidan can find one in Gates of the Abyss, chapter 5 of the Frozen Throne alliance campaign, Curse of the Blood Elves.