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EM Weaponry like lasers seem to me to be only useful as a short range defensive weapon to deteriorate incoming projectiles and drones, preventing them to impact or coming close enough for their warhead to make a difference. Why is this? Well, even in space, the diameter of a laser beam will widen considerably, thus decreasing the amount of energy per cm² impacting any object at distance, as the inverse square law tells us. A kinetic projectile does not have this drawback. Depending on the technology base, I would suggest MASERS for this purpose.

EM Weaponry like lasers seem to me to be only useful as a short range defensive weapon to deteriorate incoming projectiles and drones, preventing them to impact or coming close enough for their warhead to make a difference. Why is this? Well, even in space, the diameter of a laser beam will widen considerably, thus decreasing the amount of energy per cm² impacting any object at distance, as the inverse square law tells us. This may vary depending on the size and technology for generating and focusing the beam. A kinetic projectile does not have this drawback. Depending on the technology base, I would suggest MASERS or X-Ray Lasers for this purpose.

Edit: MASER is an acronym for Microwave amplification through stimulated emission of radiation, meaning a LASER in the microwave wavelength region. You can use other wavelength, though I would not go as far as using a GRASER as base, as gamma rays tend to penentrate the amplification mechanism...

They work perfectly fine in space, the propellant already contains the oxidant as do all explosives. But you're right that their muzzle velocity doesn't compare to the more exotic mass driver concepts.

Railguns

EM Weaponry like lasers seem to me to be only useful as a short range defensive weapon to deteriorate incoming projectiles and drones, preventing them to impact or coming close enough for their warhead to make a difference. Why is this? Well, even in space, the diameter of a laser beam will widen considerably, thus decreasing the amount of energy per cm² impacting any object at distance, as the inverse square law tells us. A kinetic projectile does not have this drawback. Depending on the technology base, I would suggest MASERS for this purpose.

They work perfectly fine in space, the propellant already contains the oxidant as do all explosives. But you're right that their muzzle velocity doesn't compare to the more exotic mass driver concepts. However, they could be used to attack drones at very close range with saturation fire.

Railguns / Coilguns

A note on coilguns: while the abrasion of the rails may be a problem, coil guns, as far as I can see, are quite inefficient in the amount of energy required, require very complex control structures to enable the magnets to work as intended, and you're required to use ferromagnetic projectiles, whereas in railguns you could use anything that conducts electricity, or use a conductive sled like a sabot and use that to propell a non-magnetic/conductive projectile.

EM Weaponry like lasers seem to me to be only useful as a short range defensive weapon to deteriorate incoming projectiles and drones, preventing them to impact or coming close enough for their warhead to make a difference. Why is this? Well, even in space, the diameter of a laser beam will widen considerably, thus decreasing the amount of energy per cm² impacting any object at distance, as the inverse square law tells us. A kinetic projectile does not have this drawback. Depending on the technology base, I would suggest MASERS for this purpose.

Particle Cannons

I think you'd need even more resources to operate them than railguns or masers. To achieve a saturation area dense enough, they might be large and require their particle "fuel". While they may be very powerful, they will probably suffer from the inverse square law.