In the Forgotten Realms, there once was the great magocracy of Netheril lead by the High Mages of Netheril, created in the year -2758 DR.
Who were/are the members of the High Mages of Netheril?
The AD&D 2e boxed set Netheril: Empire of Magic provides a whole list of major NPCs that played a significant role in the 3500 years of Netherese history. Unfortunately none of the arcanists listed under the Silver Age were alive in 1101 NY (−2758 DR). Terraseer (one of the oldest beings on Toril, also known as Arthindol), Congenio Ioun (considered the first great arcanist of Netheril, inventor of ioun stones), Ioulaum (inventor of the mythallar) were around, but it is not clear whether they were amongst the members of the council named the High Mages of Netheril.
However, we know that in 1048 NY, the number of floating cities/enclaves was already 13 (page 7 of the Winds of Netheril from the boxed set). One of them had been raised by Iolaum, and he was the ruler of his city, Xinlenal. Given that the top arcanists are said to have formed the High Mages of Netheril, it is natural to assume that these included whoever raised those enclaves into air.
Another good resource to look for candidate members is the 3e book Lost Empires of Faerûn. A blog by Xaeyruudh gives a list of all the fifty something enclaves along with citations including page numbers. Unfortunately, only Xinlenal dates back to before 1101 NY. The earliest other enclaves we have data on are Akintaer (established by an unknown arcanist in 1173 NY), Palter (established by arcanist Halavar in 1217 NY), and Orbedal (established in 1247 NY, arcanist not listed).
The one person we are sure to have been one of the High Mages of Netheril is Lady Saharel, mentioned by Elminster in the novel Shadows of Doom and later in the 3e campaign adventure Anauroch: The Empire of the Shade (page 90). Her position as a political leader was confirmed in posts from January 2018 on the Candlekeep forums. However it is not clear which age Lady Saharel lived, so it is unclear if she was one of the High Mages in 1101 NY.
Sources are incredibly vague (with Forgotten Realms Helps' History of Netheril merely listing them as "the leading arcanists of Low and High Netheril") but Champions of Ruin does describe Aumvor the Undying as one of the last Netherese Archmages though this doesn't necessarily mean he was on the council.
In the Shadows of Doom by Ed Greenwood I have found one High mage:
... Sorceress of Saharelgard, of the High Mages of Netheril...
I don't know what page it is on sadly.
there are no names given and there is no indication as to how the members were chosen (since the council was formed before the first flying city and Saharelgard never owned a city in the sky).
I am still researching but that's the only one I've found so far.