Excess Potion of Accelerated Learning: Acquired in your Garrison (part of the Warlords of Draenor expansion), this gives you a 20-percent bonus to experience from killing monsters and finishing quests. It lasts one hour, but you can buy it multiple times and use it back-to-back. Alliance players buy it from Sergeant Crowler, horde players buy it from Sergeant Grimjaw. Does not work above level 99.
Elixirs serve the same purpose as Flasks, but the buff expires if you die. You'll only use these between 1-70, generally speaking, until you can start buying Flasks which persist through death. Try not to die, and carry extras just in case. If you can't find an Elixir with the stat you want, look under scrolls, since they count as battle or guardian buffs as well.
As always, I will monitor and update this guide as new information comes in. If I've gotten anything glaringly and completely wrong, just tell me with as much data as possible. The idea is to find the fastest possible leveling method, NOT to argue about how good or bad individuals are. If you have hard data, post it! If you have an idea, let the thread know so we can test it!
K Kael'thas Alliance Kael'thas Horde Karazhan Alliance Karazhan Horde Kargath Alliance Kargath Horde Kazzak Alliance Kazzak Horde Kel'Thuzad Alliance Kel'Thuzad Horde Khadgar Alliance Khadgar Horde Khaz Modan Alliance Khaz Modan Horde Khaz'goroth Alliance Khaz'goroth Horde Kil'Jaeden Alliance Kil'Jaeden Horde Kilrogg Alliance Kilrogg Horde Kirin Tor Alliance Kirin Tor Horde Kor'gall Alliance Kor'gall Horde Krag'jin Alliance Krag'jin Horde Krasus Alliance Krasus Horde Kul Tiras Alliance Kul Tiras Horde Kult der Verdammten Alliance Kult der Verdammten Horde
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide