Oh and all of the above tooWhat's under Tirisfal. Explained early on as something that drove the magically attuned Highborne bonkers. Had no effect on the humans living there nor the Undead there now. Was stated as NOT being an Old God.
Shattered lands and remnants of the South Seas. Kalimdor was a huge continent, Pandaria was wretched free as a large floating landmass, as was Zandalar, Echo Isles etc. What else could be out there, lost to time and hidden away for 10000 years. Lost tribe of Trolls, an enclave of Night Elves from the southern hemisphere separated for 10000 years, another Titan device etc.
The deep seas of Azeroth. As annoying as it was navigating through Vashj'ir the zone was very mysterious and amazing.
The whereabouts of the Titans and even a more solid understanding of what they are.
The original appearance and nature of demons; what they were before succumbing to fel magic addiction.
The timeline prior to 12000 years, fully laid out. It's still hazy.