The Alliance uses very large numbers of drones compared to other powers, both human and non-human. This is due to both the logistical and recruitment problems faced by the Alliance.
Unlike the Turian Hierarchy, which quite literally has more manpower than it would ever need with its mandatory conscription (an actual societal problem affecting the Hierarchy for over a millennium), the Alliance struggles to recruit enough personnel to fulfill its needs. To make up for this lack of manpower, the Alliances uses drones. Another benefit of drones for the Alliance is that they don't need to be supplied with food, free time, entertainment, or communications to their home, all things difficult for the Alliance to get in bulk with its rapid expansion across the Relay Network. A drone can do a single patrol for months or even years without shopping barring some repairs, all for a relatively modest production cost and the pittance of power needed for it.
The Alliance divides the drones it uses into four categories: micro, light, medium, and heavy drones. Micros are the smallest, and are no bigger than an insect and are sometimes even smaller. Each micro drone can be produced by the omni-tool provided to all Alliance personnel, though some take longer than others. Light drones are the size of relatively small birds and mammals like sparrows and rats. Light drones are often given to Alliance marines as part of this equipment, one or two per marine, giving formation improved versatility. Medium drones are the size of larger birds and moderate sized mammals like eagles and foxes. Medium drones are usually deployed from either Alliance bases or from M26 Camels. Heavy drones are the largest drones that are used as drones instead of more like vehicles, being the size of larger animals like donkeys. Heavy drones are the largest drones that are deployed on M26s. Super heavy drones are the size of small vehicles and are used as such. They are too large to be stationed on M26s.
Most Alliance drones are airborne due to the increased versatility that provides and the ease of creating airborne drones through the use of eezo. Some others are ground based, often with an animalistic design.
The vast majority of drones in Alliance service are military and civilian drone models already for sale modified for Alliance use, usually increasing their survivability in more extreme environments.
Alliance drones almost all are powered by batteries with the ability to recharge both remotely and directly through a charging station. However, there are exceptions.
Smaller drones like micros and lights are often deployed organically within low level formations (for instance each M19 and M29 carrying a single M11 Bugeye), but larger formations of drones also exist; Lances, Flights, and Platoons. Drone Lances are a humongous in size force of drones, consisting of 12 light, 6 medium, or 1 heavy or super heavy drone. Flights consist of two Lances, often a mixture of different sizes and types. Each Flight is either deployed from an Alliance base or on a single M26 Camel. Platoons consist of six Flights and are the largest primarily drone unit. These formations have attached controllers usually deployed at a base or on a M26, but any marine with clearance can take control and direct them if needed.
Space Drones are slightly different, being controlled by the Navy and falling under their naming conventions and doctrine. The navy uses fewer drone types, but still deploys large numbers of drones. They are each controlled by either an Alliance ship or a fighter.
MICRO DRONES:
M1 Fly Scout Drones are designed to search areas nearby the user. Alliance marines often use them to check rooms before entering them or to look past corners.
M6 Mini Bee Repair Drones are designed to locate and repair damage in hard to reach areas in buildings, vehicles, equipment, and other drones.
M8 Pigeon Courier Drones are used to transport important information without the potential for radio interception revealing the information or a unit's location. They include a self district to ensure the information they carry remains hidden. They are usually produced at need or sometimes per mission using the omni-tools of individual marines.
M19 Gnat Sensor Drones are an experimental unit designed to, with the help of sensors built into a marine's harsuit, provide a 360 degree detection zone around a marine to find enemies. The M19 is currently in development, but has several problems, particularly with its power supply. Current estimates put its introduction into service being in 2160 or later.
LIGHT DRONES:
M3 Exterminator Hunter Drones are designed to destroy or disable enemy drones, though they have spent far more time taking down nosy civilian and reporter drones trying to get too close to Alliance facilities. The M3 uses electric attacks to disable drones, and are ineffective against super heavy and some heavy drones.
M11 Bugeye Overwatch Drones are designed to spot for artillery and provide overwatch for marine units.
M15 Stinger Bombe Drones are designed to ram into targets (buildings, equipment, vehicles, infantry, ect) and detonate. M15s can be equipped with multiple different payloads, but high explosives, shaped charge, gas, and shrapnel warheads are the most common. They are often used by marine Weapons Teams and are deployed from M14 Raiders.
MEDIUM DRONES:
M2 Spider Construction Drones are designed to help with construction of buildings and equipment. Often used for the final assembly of fabricated components. They have a crab or spider like design, with 8 legs, the forward 2 of which are much larger with manipulators designed to grab large objects and move them around. The other leds include tools to help with construction alongside being able to stick to most surfaces.
M5 Bee Repair Drones are designed to repair more significant damage than the smaller M6, yet can still fit in places most humans can't.
M9 Hornet Attack Drones are designed to fire an assault rifle grade mass accelerator carried in a turret on its bottom side. They are used in formations of multiple drones to coordinate fire and minimize the chance of effective counterfire.
M10 Wasp Rocket Drones are based on the same chassis as the M9, but replace the assault rifle with a micro missile launcher and a small fabricator for creating more missiles. M10s are often used alongside M9s to disorient enemies and damage larger targets. The M10 is less maneuverable than the M9 due to the greater mass of the new weapon.
M12 Yellowjacket Sniper Drones are based on the chassis of the M9, but add far more sophisticated sensors and replace the assault rifle with a sniper rifle. The M12 is used to support infantry through suppressive fire and take down important targets. The M12 is less maneuverable than the M9 due to the greater mass of the new weapon and sensors.
M13 Ranger Reconnaissance Drones are designed to provide long range reconnaissance for Alliance Battalions through their sophisticated sensors, speed, and long range. A pair of M13s carried by each M24 Panther. M13s are fixed wing and look like small aircraft.
HEAVY DRONES:
M14 Raider Harassment Drones are designed to skirmish with enemy forces, keeping them off balance and unable to rest. M14s carry a large anti material mass accelerator (the same as used on the M24 Panther) on their underside with launch pads for M15 Stinger bomb drones on their tops. They also carry small fabricators to produce more M15s and micro repair drones.
M16 Zeus Fire Support Drones are designed to provide close fire support for marine formations using their heavy machine gun (same as used on the M19), pair of micro missile launchers, and pair of anti-vehicle missiles. They are devastating but can be vulnerable to enemy fire.
M18 Aegis Shield Drones are an experimental drone design equipped with a kinetic barrier. M18s can deploy their barriers in defense of other Alliance units, providing an invaluable defensive tool to the Alliance's arsenal. M18s are deployed in some select units, with full deployment across the Marine Corp expected for the second half of 2157.
SUPER HEAVY:
M4 Hephaestus Heavy Construction Drones are designed for use at construction sites, moving things across the site and helping with construction. M4s have been used as combat platforms during pirate attacks against both Alliance and civilian (the M4 being on the open market) construction sites, proving surprisingly effective, though vulnerable to enemy fire, sparking interest in a chassis as a combat platform.
M7 Carrier Transport Drones are designed to transport items long distances through the air. M7s lack weaponry in their original forms, but the M7b added a single assault rifle turret to the chin.
DF-50 Trident Fighter Drones are almost identical to the F-50 Tridents, with the only difference being its drone nature. DF-50s are controlled by F-50s in the same formations as them.
DPF-51 Bident Patrol Fighter Drones are almost identical to the PF-51 Bidents, with the only difference being its drone nature. DPF-51s are controlled by PF-51s in the same formations as them.
M17 Cyclops Assault Drones were based off the same bipedal chassis as the M4 Hephaestus drones, but are equipped for combat. Each M17 has a heavy machine gun in its right arm (the same type as is used on the M19), and a missile pod in the left arm capable of carrying many types of munitions. The M17 is equipped with an extremely powerful electronic warfare and communications system, allowing them to serve as local nodes of control even in heavily jammed areas. M17s have heavy armor, increasing their mass and lowering their speed compared to the M4. This has caused problems for the Alliance's plans for the M17, as their low speed make them unappealing for the highly mobile Battalions of the Alliance Marine Corp. This has left the M17 as primarily a guard unit, protecting Alliance bases and facilities.
Unit List:
Micro:
Scout
Repair
Sensor
Courier
Lights:
Overwatch
Hunter
Bomber
Medium:
Attack
Rocket
Sniper
Reconnaissance
Repair
Construction
Heavy:
Fire Support
Shield
Harassment
Super Heavy:
Transport
Heavy Construction
Assault
Fighter
Patrol Fighter
Deployment Timeline:
M1 Fly Scout Drone: 2149
M2 Spider Construction Drone: 2149
M3 Exterminator Hunter Drone: 2149 (M3b in 2153)
M4 Hephaestus Heavy Construction Drone: 2149
M5 Bee Repair Drone: 2149
M6 Mini Bee Micro Repair Drone: 2149
M7 Carrier Transport Drone: 2150
DF-50 Trident Fighter Drone: 2150
M8 Pigeon Courier Drone: 2151
DPF-51 Bident Patrol Fighter Drone: 2151
M9 Hornet Attack Drone: 2151
M10 Wasp Rocket Drone: 2151
M11 Bugeye Overwatch Drone: 2151
M12 Yellowjacket Sniper Drone: 2152
M13 Ranger Reconnaissance Drone: 2152
M14 Raider Harassment Drone: 2153
M15 Stinger Bomb Drone: 2153
M16 Zeus Fire Support Drone: 2154
M17 Cyclops Assault Drone: 2155
M18 Aegis Shield Drone: late 2157
M19 Gnat Sensor Drone: Unknown