Someone in another thread was talking about using their hover drone as a camera, having it follow them around for some celebrity shenanigans. That (plus looking up images) got me thinking about what other "mundane" uses exist for drones, and what justifications one might have. Especially since a combat drone with a giant gun might just be a small tank, you know? I'll list some examples and if any more occur to you, feel free to contribute the ideas.
Mining: Combat drone with a heavy "mining" laser.
Maintenance: Any drone with more tools than guns.
Personal Assistant: Manipulator arms, buddy computer with an artificial personality.
Camera: Hover drone with a camera.
Cargo Mule: Especially viable in colonies and on rimworlds.
Gonk!: He charges my batteries.
Construction: Similar to cargo, but with manipulators.
Having trouble thinking of ones that can justify carrying a weapon. Might make it difficult to take them places. Any thoughts?
Bodyguard drone could work, especially if your mechanic is an icon.
Courier: Any fast drone. A weapon might just mean it's secure.
Autodoc: With the right tools and maybe short range 'weapons'.
Chef: Blades. And style.
Firefighting bot: Armor, sensors, a tool or two, and a weapon suitable for cutting/breaking walls or doors.
Lumberjack: Climbing ability, rugged, a weapon suitable for cutting down trees.