Sabers (A-F | G-M | N-Z) | Archers (A-C | D-M | N-Z) | Lancers (A-F | G-M | N-Z) | Riders (A-F | G-M | N-Z) | Casters (A-F | G-M | N-Z) | Assassins (A-F | G-M | N-Z) | Berserkers (A-F | G-M | N-Z) | Extra (Rulers | Avengers | Moon Cancers | Alter Egos | Foreigners) | Unclassed | Beasts | Chaldea Security Organization | Villains (Observer on Timeless Temple Villains | Epic of Remnant Villains | Cosmos in the Lostbelt Villains | Crypters | Event Villains) | Other Characters
There are additional Classes and designations that do not fall under the seven "regular" Classes summoned as part of the Holy Grail War ritual. These fall under the umbrella term of "Extra Classes", and are typically only summoned under extraordinary or taboo circumstances. As the Grand Order and the FATE summoning system do not operate under the rules of a Holy Grail War, such Servants are far more common during the events of Fate/Grand Order.
While many Extra Classes exist, like Gunner, Saver, or Funny Vamp, only six have appeared thus far in Grand Order: Shielder, Ruler, Avenger, Moon Cancer, Alter Ego and Foreigner. The classes of Ruler, Avenger and Moon Cancer make up their own class triangle with Avenger beating Ruler, Ruler beating Moon Cancer, and Moon Cancer beating Avenger.