Space Fighters-Highly, highly averted by just about everybody in the Equestriaverse. What most people would call a “fighter” is the Autonomous Combat Vessel (ACV), which can be accurately described as “an armed drone with a glandular problem”. With only one exception, they’re run by an AI or an uploaded personality, and are considered expendable as needed by their various forces. With few exceptions, they are carried by dedicated tender craft, and are mostly used as a shield against Changeling ACVs (whom use ACVs as their primary long-ranged weapon) and as a “scouting with teeth” option for fleets.
For the Royal Equestrian Space Forces, they use the Spike-class ACV, which is pretty much a 3 cm buster launcher, two point defense turrets, a reactor, a gravity drive, a computer core, sensors, and just enough hull and armor to provide some protection for the whole affair. Spike-class ACVs have external clamps for four missiles, but they are rarely used as missile carriers. Their primary role in the RESF is to engage other ACVs and engage damaged/crippled warships, rather than be expended against an intact fleet’s defenses.
The Imperial Griffin Space Navy has two ACVs in service with the fleet-the Spur-class ACV and the Valkyrie-class ACV. The Spur-class is slightly smaller than the Spike-class, mounts a fast-cycling 2 cm buster launcher, and is more dedicated to the anti-ACV role than the Equestrian Spike-class. The Valkyrie-class ACV, on the other hand, is built for the anti-ship role, mounting a 3 cm buster launcher and carrying four Asp anti-ship missiles on external clamps. In fleet actions, Valkyrie-class ACVs will engage escorting warships on the fringes of a fleet, cripples, and anything else that is relatively vulnerable.
For the Senate and Minotaur Republic Forces, the idea of creating a sapient AI that would not be able to choose when it was created to serve as an expendable weapon is abhorrent. The nearest class of ship that fills the same role as the ACV is the Hammerhead-class battle rider, which is essentially a corvette-sized warship without a Tunnel Drive, carried into battle by SMRF warships of battle cruiser sized or smaller. Armed as well as a frigate, the Hammerhead serves as an attrition platform and a defensive platform for planetary defense.
The Changeling Empresses and Queens use the Larva-class ACV exclusively as their long-ranged engagement platform. Unlike other races, the Larva-class is technically “crewed”-a specialized adaptation of the standard Changeling drone is used as the wetware AI for the drone. Since Changeling Nymphs, Queens, and Empresses can communicate instantly at interplanetary distances with their drones, this makes their ACVs more dangerous because they can be controlled instantly. Armed with a 4 cm buster launcher, it is slower firing than most other races ACVs, but it can do a significant amount of damage. And, if necessary, it can always ram a hostile warship. They are, after all, expendable.