Lesser Scroll of Replenishment

Regenerates 250 hit points and 100 mana of the Hero and nearby friendly units over 45 seconds.

This scrolls resembles a replinishment scroll, but is only half the length of that item and confers a reduced effect.

Source
Maiev can find one in Broken Isles, chapter 2 of the Frozen Throne sentinels campaign, Terror of the Tides.

Kael and Lady Vashj can find one in A Dark Covenant, chapter 2 of the alliance campaign, Curse of the Blood Elves.

Kael and Lady Vashj can fine one in The Crossing, the secret level of that campaign.