Useful zone-specific buffs

Many high-level zones provide buffing and potion-like non-food items, some of which are useful for end-game activities. These can be collected repeatedly, but only after completing certain quests in the zone. Thes buffs are zone-specific in that you need to go to a specific zone to get the buff, collect the reagents, or make the item.

Felwood Plants
You must first complete the quest given by Arathandris Silversky (Alliance) or Maybess Riverbreeze (Horde), who can be found near the road to Emerald Sanctuary. You will be given a, which, when held in your inventory, allows you to collect from mobs in Felwood. You can also collect other drops based on your profession. For example, you will collect Fel Creep every time you gather herbs or Tainted Vitriol every time you mine ore. These items only drop in Felwood. You can repeatedly turn in quantities of these items to the NPC and get two Cenarion Plant Salve in exchange.

You can then use the salve to cleanse the corrupted plants that spawn at certain set locations around Felwood. A cleansed plant gives you a reward and then can not be interacted with for a while. 25 minutes after a cleansing, you (or any other player) can harvest the plant again without using salve. Eventually, the plant will despawn or respawn as a corrupted plant. All these items are on a 2 minute cooldown shared with healthstones and other "non-aggressive" items (but separate from potions.) After the appropriate amount of salve is applied, the plant changes to "Cleansed &lt;plant name&gt;". Some of the items produced are not technically buffs, but are listed here for completeness.

Map of plant locations

Winterspring Juju
Witchdoctor Mau'ari is in Everlook will give you Juju items when you bring her e'ko, which you can sometimes get from creatures throughout Winterspring. You need to have the Cache of Mau'ari with you to collect the e'ko, and also to use the Juju once you've received it. You must complete two quests for her first. As of patch 1.12.2, it is most efficient to farm E'kos in a group or raid. If you are grouped and an E'ko drops, everyone in the group/raid gets to loot one, provided they meet the above prerequisites. If you already have plenty, you can help out others by just being in the group to make an extra one drop and giving it to them! These buffs do NOT stack with castable buffs!

Jujus are now available to both Alliance and Horde.

Un'Goro Crystals
Throughout Un'Goro Crater, as you may have noticed, are lots of multicolored crystals growing out of the ground. If you collect them, you'll be able to use them in the 3 pylons located in the North, East, and West areas of the crater to produce items that you can use at any time to give you a certain buff. You need to complete the Crystals of Power and Making Sense of It quests to be able to use the pylons.

These buffs do NOT stack with castable buffs! These buff items can be used on friendly targets.

Blasted Lands Blood Elves Concoctions
There are two Blood Elves in the Northeast corner of the Blasted Lands who will give you certain items when you bring them certain parts from the animals in the area. It's pretty obvious which parts come from which animals. All of the concoctions are unique so you can only carry one of each at a time; however, you can carry as many of the ingredients as you have bag space for. Upon turning in each quest for the very first time, you will receive the buff of the concoction rewarded in addition to the concoction itself. You may only have one of these five buffs active at any given time (i.e. they do not stack with each other).

They stack with castable buffs, but counting as a battle/guardian elixir, the do not stack with other elixirs of the same type.

All concoctions have a shared 60 min. cooldown.

Sayge's Dark Fortunes
Sayge is a Gnoll who works at the Darkmoon Faire. He can "read" your fortune through a couple questions he asks you, and depending on your answer, he'll cast a certain buff on you as well. You'll also receive an unrelated scroll, most of which are worthless, but some of which give you a quest.

These buffs do NOT stack.

Mangletooth's Revenge
Mangletooth is a Razormane Quillboar who has been captured by the Taurens of Camp Taurajo. He still desires his revenge against the Bristleback Quillboar tribe, and will assist you in carrying out their defeat. Bristlebacks carry Blood Shards, which you can trade to Mangletooth for his buffing assistance. These buffs are applied directly to the player as the reward for turning in the specified number of shards.