I would totally recommend using Zygor's if you are leveling alts or don't care about the quests you're doing, because it offers a huge leveling advantage in terms of streamlining what you do. Just let the arrow tell you what to do and you never have to think about where you're going or what you're doing. When I use this addon (and the leveling guides) I definitely understand why he charges for it.
Nightborne - "Isolated behind a protective barrier for 10,000 years, the elves of Suramar grew increasingly dependent upon the arcane magic of the Nightwell. To protect this font of power, the leaders of the Nightborne struck a bargain with the Burning Legion that plunged their kingdom into civil war. After fighting for freedom from their demonic masters, the Nightborne seek allies in the Horde to help them reclaim their place in the world."
Azerite equipment is currently balanced around being able to unlock the outermost, earliest tier of power immediately upon acquisition, while delaying further advancement until the Heart has been further empowered. For example, the first piece of Azerite equipment, gained shortly after the Heart itself, is fully empowered once the Heart of Azeroth has reached level 3. A character at 120 (the maximum for the expansion) may find a piece whose first tier requires the Heart to have grown to level 12 or greater.
Isle of Quel'Danas: Special mention. At lvl 70 you can start doing the dailies here. Despite not being able to fly, the quest density is VERY high. I recommend hitting this every reset if you spend more than 24 hours REAL time(not /played)in the 70-80 level range. In fact, if you're doing a monk and only logging in once each day anyway, IQD WILL be your best exp/h for this level range.
Vol’Dun is the hardest and most tedious of the Horde Zones in Battle for Azeroth. It’s also probably the one that makes the most sense. Each sections of quests leads directly to the one you should do next. For all of these reasons it’s going to be best to get this one done early. Thanks to any legendary items you might have collected in Legion, you’ll be strongest in the leveling process before 115 and weaker after — because that’s when the legendary effects stop working.
For reference, my previous best time abusing Method-0 in 7.3.5 was 32.4 hours(as show in the old thread). A difference of just over 8 hours; which isn't all that bad, all things considered. And I believe I made several errors along the way, which could be cleaned up in future runs. I believe that that gap could be significantly closed by using a monk's bonus, but I hate playing monk...so...yeah. YMMV