Lesser Replenishment Potion

Regenerates the 150 hit points and 50 mana of the Hero over 30 seconds.

Source
Malfurion, Tyrande, and Maiev can find one in Balancing the Scales, chapter 5 of the Frozen Throne sentinels campaign, Terror of the Tides.

Malfurion and Maiev can also find one in The Ruins of Dalaran, chapter 7 of that campaign.