One of the most important ways to heal up after taking damage is your Health Potion. Every character has one by default starting from level 1 which can be used every 30 seconds to heal up to 60% of your total HP. Apart from adding more hit points to your character, their effects can also be buffed with the secondary affix Health Globes and Potions Grant +xxxxx Life on your items, the Invigorating Gemstone legendary gem or the Necromancer's Leech Blood Flask.
While grinding for items you can find legendary potions as a rare drop. These have exactly the same healing ability and cooldown, but also provide a small special effect on top that can come in quite handy in certain situations. Below you will find all the different potions that are in the game roughly sorted by their general usefulness or popularity. To use their effects, you either need to have less than full HP or unlock any of three potion-related Altar of Rites nodes Mother, Mortal or Father. Some builds and classes have a clear preference for a specific potion to improve either their DPS, survivability or resource generation, so have a look!
Bottomless Potion of Kulle-Aid
Description Overall the most impactful Legendary potion in the game. It fits into almost any build and helps you to destroy walls spawned by elite enemies. With good timing right before your nuke you can often improve your DPS signifcantly, especially on ranged builds. In groups, it's one of the most important jobs as a support player to destroy walls in the right moment using this potion. Sometimes the potion doesn't work and your character will still try to move around walls, so be wary (especially with moving-while-channeling skills such as Strafe).
Used for Most pushing builds, especially ranged DPS and Supports.
Bottomless Potion of the Unfettered
Description Up to 7 seconds crowd control immunity is massive for builds that otherwise can't avoid fear, stuns, knockbacks or freezes. This is usually the case for almost every intelligence build in the game, as all three classes lack useful ultimate skills similar to Vengeance or Wrath of the Berserker. Using it right before your nuke will help you in many cases.
Used for Intelligence classes, especially slow and channeling builds.
Bottomless Potion of Rejuvenation
Description Resources can be a real issue for some builds and this potion can help you out. If you use it below half HP, you recover up to 30% of your primary resource.
Description Increases your Life per Kill by a significant amount to the point where you can heal to full with a single attack while farming. It's also a key component for recovery in the Demon Hunter's Impale build where you can snapshot the increased LpK into your Shadow Power to improve your healing.
Used for Mostly the Shadow's MantleImpale Demon Hunter and for extra healing from kills.
Bottomless Potion of Amplification
Description This potion gives you increased overall healing for a short time after using it. Usually this is not helpful as you most likely end up on full HP anyway, but it can be combined with Molten Wildebeest's Gizzard for getting a bigger shield as your sheet Life Regen is increased during its effect. The effect also works for itself, giving you 75% healing instead of 60% when you press the button.
Used for Overall most useful "healing-only" option.
Bottomless Potion of the Tower
Description This potion gives you more Armor for a small duration, helping you to mitigate heavy attacks.
Used for Niche defensive option (especially for builds without any other noteworthy recovery such as Akkhan's Bombardment or most shield-base Wizard builds).
Bottomless Potion of the Leech
Description Increases your Life per Hit for a short time. The effect is rarely noticeable unless you have extreme Attack Speed.
Used for Niche healing option (especially for very high Attack Speed builds).
Bottomless Potion of the Diamond
Description This potion gives you up to 100 All Resistance to help you survive heavy incoming damage. Unfortunately the value is quite low and typically the utility potions are a better choice.
Used for Niche defensive option (especially for Strength and Dexterity builds with little other recovery and with Stone Gauntlets active).
Bottomless Potion of Regeneration
Description This is the worst of the healing-based Legendary potions. It gives a tiny amount of Life Regeneration for a few seconds and doesn't do much beyond the regular healing effect.
Used for Niche healing option if you have no better Legendary potions available for that purpose.
Bottomless Potion of Chaos
Description This potion teleports you a short distance in a random direction. It is considered absolutely useless and in most cases even dangerous to use (especially on Hardcore) due to its unpredictability.
Used for Perfectly teleporting yourself into ongoing Molten explosions!
Bottomless Potion of Fear
Description Even worse than the Bottomless Potion of Chaos. This one lets your enemies run away from you, effectively destroying the pull you have been trying to make. In farming you could theoretically proc Rechel's Ring of Larceny with it if you manage to take some damage, which is usually something to avoid as most builds there run with Squirt's Necklace at the same time. In general, you should avoid relying on Fear as a defensive mechanic as it ruins your offensive capabilities and rather look for other ways of improving your survivability.
Used for Proccing Rechel's Ring of Larceny, otherwise to be avoided (use regular potion instead).