Max Revive is a rare item that debuted with the series in Generation I. This item will revive a fainted Pokémon AND restore all of its HP. It's better than Revive in the sense that all HP gets restored, but the offsetting factor is that Max Revive is not available for sale at any Poké Mart. Max Revive can only be found via collecting an Item Ball that contains one, finding it on the ground as a hidden item using the Dowsing Machine, or-starting in Generation III-being found by a Pokémon that has the Pickup Ability.
Related ThreadsMax Revive Glitch? - last post by @ Aug 5, 2010
revival herb confusion - last post @ Jan 19, 2011
legindairy battle hurt heal revive - last post by @ May 20, 2007
The Sky Rescue Forum Revived - last post by @ Aug 12, 2011