"Drones are small, lightly-armed combat robots equipped with very small mass effect fields that allow them to levitate. They are also equipped with basic VI programming allowing them to adapt to changing situations on the battlefield, and have a small amount of shielding.
Combat drones tend to be deployed in wings as 'cannon fodder', creating distractions for marines to operate safely. Soldiers refer to friendly drones as 'flocks' and enemy drones as 'swarms'. Drones are a key element of the Alliance's military initiative, but they are also used by the geth." 
Types of Drone:
- Advanced Assult Drones
- Advanced Rocket Drones
- Defense Drone
- Surveillance Drone
- Message Drone
The Migrant fleet has a veritable swarm of repair drones monitoring the outer hull of the ships at any given time. These drones are from the last several decades of production, repaired and reprogrammed until they're finally broken down for scrap and spare parts.
- SaniDrone: A program and some simple modifications that allow a drone to sanitize a small area using low levels of radiation. Pretty much standard on any quarian-programmed drone.
- VI mods: Personality interfaces as complex as Glyph or AVINA, to simple 'pet' personality simulators such as used in KEI-9 model FENRIS mechs.