Not sure if this has been addressed.
It seems to much in our faces not to be asked.
Based on what we know from the Legion announcement up to right now in beta, there are 5 pillars of creation we search for:
Stormheim - Aegis of Aggramar
Azsuna - Tidestone of Golganneth
Suramar - Eye of Aman'Thul
Highmountain - Hammer of Khaz'goroth
Val'sharah - Tears of Elune
Some are received at end of dungeons, I would think the Eye of Aman'Thul is received by Gul'dan at end of Suramar raid...
...but
In the area of Dalaran where we place the pillars there is a 6th pedestal. I'm sure that isn't a simple mistake Blizzard has yet to correct this far into beta.
Has there been any speculation or clues as to a possible 6th pillar of creation? And if so, what could it be?