Mageocracy

A mageocracy, alternatively spelled magocracy, is a system of government in which power is held by magic practitioners, particularly arcane magic users. The actual structure of the government can vary, though often it is ruled by a council.

Age of Arcanum
Many if not all of the flying cities of this era were mageocracies.

Aeor
Aeor was a mageocracy that was destroyed by both the Betrayer Gods and Prime Deities for its belief that mortals should eliminate the divine pantheon.

Avalir
Avalir was ruled by the Septarion, a 7-person council of mages, some of whom had sat upon this council since the city's founding. The Ring of Silver and Ring of Gold also consisted of mages.

Zemniaz
The city of Zemniaz was overseen by the council of Zeidel, which held public debates on many important issues. Halas Lutagran, a former member of that council, was frustrated with the degree of bureaucracy in this system.

Post-Divergence
There are no confirmed mageocracies as of yet in modern Exandria, but the magic guild held a particularly strong role in Draconia prior to its fall, and the Cerberus Assembly, a mage council, is closely tied into the governance structure of the Dwendalian Empire.