[url=http://magerune.blogspot.com/2014/01/dreadglare-spellsire.html]Dreadglare the Spellsire[/url] is always available.

[url=http://dndtools.eu/classes/beholder-mage/]Beholder mages[/url] give up their central eye though, and their eye stalks become "spell-stalks" instead as they gain levels, with each capable of casting one spell of a particular level each round as a free action. So each round, a 10th-level beholder mage can cast up up to 10 spells using its "spell-stalks" as a free action, as long as they are all of a different level, 0th-level through 9th-level.

Their casting is Intelligence-based, they learn spells like wizards, but know and cast them on the fly like sorcerers.

They are pretty nasty.