Dawn of War: The Blood Ravens' Chapter Master is also the chapter's Chief Librarian, the designation used to refer to its most senior psyker. However, after Dawn of War III, this tradition is broken, as the new Chapter Master Gabriel Angelos is not a psyker at all.
EXTRAPOWER: Blackberry's goal in reviving the ancient wizard Diamond Mine is to create rulership of mages over the world and humanity, led by the ancient and powerful Diamond Mine himself. Zophy and his companions oppose her believing that he would be a Sorcerous Overlord. Given that his followers in ancient times had sealed him inside a diamond, they might be onto something. In Attack of Darkforce, she misses out on the window to fully revive Diamond Mine and instead performs a ritual to become the second generation Diamond Mine — Diamond Black. It remains to be seen whether she becomes the Benevolent Mage Ruler she imagines or a Sorcerous Overlord for Zophy to bring down. The wizards of her old hometown of the Hidden Elf Village Ispares, meanwhile, are supportive of her attempts to either revive Diamond Mine or claim his power: as Manuela puts it, it can be useful for the wizards if their childhood friend enforces magic rulership.
Final Fantasy IV has the Epopts of Troia, a group of white magicians and diviners. Mysidia is also this, although it's more theocracy than a typical government.
Final Fantasy VI has a variation of this; in a world where magic is dying, only the highest-ranking officers in the Gestahlian Empire are trained in Magitek technology, using leftover magic harvested from the world's Espers. And then there's just Kefka.
In Final Fantasy VIII, Galbadia becomes a type of magocracy once Edea puts a lightning bolt through the president's chest and assumes command. There's also Esthar, which was ruled by the sorceress Adel, who was so cruel that the people revolted and she was sealed up in space.
In Final Fantasy XI, the Federation of Windurst has such a government. It is led by the mystic Star Sybil, with five ministries headed by powerful mages.
Dalaran in Warcraft. It was the smallest of the human kingdoms, but rather influential. That is, until the Scourge and Burning Legion ravaged it.
Now after years of renovations it's back and has moved (quite literally) to Northrend as the new central city in the Wrath of the Lich King expansion. It is the first city in World of Warcraft to float in midair. Players of the mage class get an automatic head start with the city's faction, the Kirin Tor, being at Friendly level right out of the gatenote This lets them have access to the faction's tabard, which allows them to champion the faction in dungeons and get reputation very quickly.
Warcraft is pretty much full of Magocracies. Another example would be the Blood Elven kingdom, Quel'Thalas, where the 'Magisters' are seen in almost every position of authority. Though that may be because every Thalassian is capable of, at least, very basic magic — to which they are literally addicted. If you want to stretch it, the Night Elves of Darnassus are ruled by nature-wielding druids and divine magic-wielding priestesses.
Deyja, the Kingdom of the Necromancers on Antagarich in its first appearance seemed to be a Necrocracy, but later turned out to be closer to this trope, as at least two modern-day kings of Deyja that took over with support from the necromantic ranks were quite living, but still mages. The general impression is that Deyja is a magocracy with feudal trappings transitioning towards being the "magocracy of undead wizards" type of necrocracy but not quite there yet.
The Sorceresses and Warlocks were implicitly this in the first Heroes since they were mage-ruled (as indicated by the name of the factions) and fought over the throne of Enroth. The second game downplayed it by having them all be subsidiary to the Kingdom of Enroth (note the point in the trope description on how having king who just happens to be a mage doesn't count — one or both of the contenders for the throne might have been mages, but it wasn't part of their claim to the throne).
The stand-alone mission pack Heroes Chronicles partly takes place before the founding of the Kingdom of Erathia and has the Bracadan mages ruling over the barbarian clans. The player, in the form of the barbarian Tarnum, must unify the clans and overthrow the mages. The collapse of Bracaduun (Bracada is the name of the smaller successor state. Mostly magocratic, as well, though the same immortal mage ruled it throughout its entire existence) led directly to Erathia's establishment, as the first King Gryphonheart was a Knight of Bracaduun before Tarnum broke Bracaduun.
The Psijic Order is one on their home island of Artaeum. They are governed by a magical council led by the Ritemaster (or Loremaster in some sources). The oldest monastic group in Tamriel, the Psijic Order is a secretive Magical Society founded during the ancient times by an Aldmeri (Precursors to the modern races of Mer) sect who rejected the transition to Aedra worship from ancestor worship, known to them as the "Old Way" or "Elder Way." Their order is highly selective and they practice Sufficiently Analyzed Magic which allows them to perform feats (make their island disappear, freeze time, astral project, etc.) that no other group in Tamriel can match (save for the extinct Dwemer).
The Tevinter Imperium is an ancient Magocracy based on Rome and Byzantium, with the Tevinter equivalent of the Roman Senate chosen from the Circle of Magi with the Grand Enchanter (Leader of the Circle) becoming The Archon (Tevinter equivalent of Emperor) after the death of the previous Archon. We have yet to actually visit it and it's a Vestigial Empire by now, but its atrocities are the main reason mages get a bad rap in Thedas. Their first act was to declare war on the elves, obliterate most of their culture, and enslave them (along with anyone else they don't like). Then they tried to break into Heaven — or rather, the Golden City at the heart of the Fade, said to be the home the Maker made for his children. What happened next is unclear, but the city turned black, and the Darkspawn taint was created, starting a vicious cycle that has persisted for centuries.
The Legacy DLC for the second game reveals that the first darkspawn were actually corrupted Magister Lords. However, it's implied that the city was never golden to begin with, and was already "corrupt" when they got there...
Tevinter ex-slave Fenris also points out that Tevinter isn't friendly to most Magi either. Only a few Magisters enjoy any power and privilege — the rest are little better than slaves. "The magisters do not hesitate to collar their own kind."
Tevinter is described as a Vestigial Empire in the first game, but the second game reveals more about it, and the Imperium is actually still quite strong, just not in the Southern part of Thedas, which they don't really much care about anyway. Besides, their hands are pretty full with the Qunari's constant attempts to invade.
The third game, with potential Tevinter companion Dorian and a few other secondary Tevinter characters and the game's Big Bad gives some more exposition on it from the point of view of people who lived there. Dorian truly loves (most of) his people and his country, but despises the corruption, the abuses of power, the sense of entitlement the ruling mages have about themselves, and that there's justified hatred of the nation by others. Various missions and messages that come up during the game reveal he's not alone in believing that. He also explains that Tevinter's government isn't too different from other nations. Power still mostly remains in old noble bloodlines. The main difference is that they all just happen to be mages. The idea that mages rule Tevinter, when the reality is that noble families of mages rule it, is meant to give false hope to commoners that their families' lot in life could improve if they sire a mage. But 99 times out of 100, they'll just end up glorified desk clerks, which may be a step up from being a mud-farming peasant, but they'd still be far from calling the shots.
The Shapers of the Geneforge series. They pretty much rule the world with an iron fist; they come down very hard on anyone who tries to learn Shaping (using essence to create and alter new forms of life) without their permission, or any beings created by Shaping that are less than fully subservient. Even "conventional" mages generally find their studies hampered by the Shapers and their restrictions on magic. Unsurprisingly, more than a few Muggles and intelligent creations have Turned Against Their Masters.
The Shapers have good cause to be repressive, however. Unrestricted Shaping can lead to catastrophe in dozens of different ways: disease, ecosystem destruction, rogue creations breeding, and individual Shapers going mad with power to name a few.
Dark Souls has the city-state of Vinheim, which is run by the Wizarding School called the Dragon College. You don't get to personally go through, but you do meet several characters from the area.
Star Wars: The Old Republic features an Empire ruled by the Sith Emperor, who tends to leave running the place to his Dark Council these days. That Dark Council being made up entirely of Sith Lords. Those who cannot use the Force find their opportunities to advance in the Empire rather limited and their lives ruled by the whims of the Sith.
In the lore of League of Legends, virtually all nations in history are said to have been ruled, either openly or covertly, by magicians, specifically summoners, who would use their magic to empower their own armies while devastating the enemy's. When this wanton use of magic started threatening the very integrity of the world itself, they then got together to form the titular League to serve as an arbiter for all future conflicts, so that they can be resolved without such destructive wars; the League now seems to want to play this role to the entire continent of Valoran (where the game notionally takes place and from where most of the playable champions originate), though not everyone is happy with this.
Now averted, with summoners having been Retconned out of existence. However, the game still has an example: it's said that Noxus, the Social Darwinist state that constitutes one of Valoran's two superpowers, was a Magocracy in all but name when the royalty still ruled, with the Black Rose, a cabal of power-hungry magicians, wielding the real power. Boram Darkwill's coup put an end to this, apparently at least, transforming the city into an Asskicking Leads to Leadership military dictatorship (though Darkwill himself is implied to have been something of a Sorcerous Overlord). Now that LeBlanc, the Black Rose's leader, has reappeared and seems to be quite chummy with Swain, a former Black Rose member who's usurped Darkwill's position, however, Noxus may be heading back towards Magocracy.
Timespinner's Vilete was a rather fascist example of this, treating non-magical citizens as disposable and almost sub-human.
Shows up multiple times in the Lunar series of games:
In Lunar: The Silver Star and its remakes, Vane is a magical city on a floating island designed to guard the Goddess Tower, which it slowly circles. It is inhabited and ruled entirely by mages and is the home of the Magic Guild, who are responsible for the research and instruction of magic across the world. Indeed, to even access the city hopefuls have to prove their magical ability by fighting their way through the Vane underground, which is filled with monsters resistant to physical attacks and weak to magic.
In the sequel Lunar: Eternal Blue, Vane still exists but it remains landbound, after being blasted out of the sky by the Grindery in the previous game 1000 years earlier. Since the previous game, the Magic Guild has largely disbanded and Vane is populated by both magical and non-magical inhabitants. Lemina, one of the game's heroes, is a descendent of the ruling family of Vane and seeks to restore it to its former glory. It's a goal she (sort-of) shares with the Evil Sorcerer Borgan, who establishes Neo-Vane, an artificial version of the original Vane that, like its namesake once did, only allows people with the ability to use magic to enter the city. However, unlike the original, anyone who does not possess any magical aptitude is instead enslaved and sent to the Zaback mines. After witnessing the atrocities of Borgan and Neo-Vane, Lemina abandons her plan to return Vane to what it once was.
