[@Keyguyperson]We can perhaps help differentiate by making these coilguns/railguns large spinal mounted monstrosities. Well, not quite taking up all space in the ship but rather it requiring length. There's only so much acceleration you can impart on a projectile before it's no longer a projectile. On the other hand there's a minimum velocity you'd want for the projectile otherwise it'd take too long to reach or would be too slow to be a viable threat. Based on these I devised quite a few weapon types that might use similar technology yet have completely different roles.[hider=Weapon Types]
[b]Launcher/tube:[/b] Coilgun mechanism giving some initial velocity for the missiles. They are relatively compact and only help to give distance between the ship and missile before the latter's engines fire. If neccessary you can also distinguish between missiles that only get the minimum speed and torpedoes which get a decent starter velocity from a longer coil.

[b]Mass Driver:[/b] Coilgun system accelerating heavy mostly inert munitions for orbital bombardment. Think of Rods of God and similar ideas.

[b]Spinal Accelerator:[/b] Long coilgun system which accelerates a relatively small guided projectile towards the target. It might run through the entire length of smaller ships but the largest ships might not need that much. Or alternatively do it for even faster and deadlier projectiles.

[b]Heavy Spinal Accelerator:[/b] More likely to be used for large warships, these shoot more complex projectiles which might have warheads, better maneuverability or other desirable features. The said projectiles are also tend to be larger for the same reason. As complexity makes them more sensitive to acceleration they need length to compensate which makes them only fit for the larger warships.

[b]Plasma Accelerator:[/b] Normally acceleration limits mean you need considerable length of coil to achieve decent velocities. In case of the plasma accelerator though they abandon that caution and use almost tiny amounts of matter accelerated to often even higher velocities than normal. Plasma weapons are deadly but generally plagued with short range as they cannot be guided and worse the plasma tends to rapidly disperse. You could even say they're the shotguns of space warfare.

[b]Dust Accelerator:[/b] Another method to overcome the length limits is using even less complex yet still solid projectiles. Dust accelerators fire nothing but dust or even singular crystal structures of a solid (usually tungsten) in a continuous stream. They are effectively like particle beams but often slower. They compensate this with much better throw weight and reduced dispersion. Best comparison is a water cutter but with far larger velocities and raw power. This is the "Death Ray" as imagined up by Nikola Tesla.

[b]Particle Accelerator:[/b] An alternative to lasers. The two weapon types share a lot of features but lasers disperse less and overall longer ranged. On the other hand particle cannons can have more penetration and spread deadly radiation if impacting with certain materials.

[b]Coilguns[/b] Compact gun systems rarely used in ship to ship combat due to their low velocity, nor are fit to intercept most projectiles and missiles for the same reason. On the other hand they can have a decent punch for their power unlike lasers so they are sometimes used to deter opponents and smallcraft at "knife fighting" ranges.
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Also I think there are more alternatives than just orion drives and torchdrives. Last time I worked with somebody on a realistic "near future" space NRP setting. I distinguished the following methods.
[hider=Willy's list on propulsion]
[b]Laser Propulsion:[/b] As others said letting nuclear power in the hands of civilians is a bit iffy. Sure, powerplants are safe but just turning that torch the wrong direction could be a giant mess. So my idea was to establish a network of gigantic lasers that can propel most civilian craft in space. Their acceleration is kind of low and they require other alternatives like rockets, elevators or mass drivers to escape gravity. On the other hand it's constant so it's overall better than most alternatives for long tours.

[b]Annie Drive:[/b] Annie is antimatter safely embedded in molecular bonds which can be stored like a powder. It only has the tiny fraction of antimatter's energy density but it's safer than even rocket fuel and easy to use. It saves up a ton on complexity compared to nuclear drives and very mass efficient as propellant. As such small military craft loves this. On the other hand it's kind of expensive to make thus annie powered vessels only move when necessary and even prefer carrier style warfare. That and hitting the fuel reserves has a good chance of the ship blowing up like an improvised nuke. Absolutely not recommended for civilian use. Another drawback is that annie drive vessels still need an independent power source to the rest of their systems. So the more energy-consuming is a ship, the more you want a reactor+torchdrive rather than annie drive.

[b]Torchdrive:[/b] Vessels that use nuclear power (either fission or more commonly fusion) to burn inert fuel and let that propel the ship. Unlike annie drives the torchdrives are generally safe and the worst you can get is radiation leak or accidents at the torch end of the ship. On the other hand compared to rockets this tend to be massively energy demanding and needs a beefy reactor to do so. The massive heat also make them a bit nasty at takeoffs so if possible torchships don't do that. Large ones might not even be designed to ever land. Compared to annie drives the torchships are relatively cheap to fuel (depending on reactor and inert fuel characteristics) but they have a large "sink cost" in building the power system for them.

[b]Pulse Drive:[/b] Nuclear propulsion for less sophisticated needs. They can be mostly described as detonating nukes behind the ship for propulsion. The simplest designs do literally just that which is terribly inefficient compared to torch drives. More sophisticated desings use micro nukes within a reflective chamber to utilize large percentage of the energy while achieving a more continuous propulsion. Some of these designs might even have benefits over the torch and annie drives but generally only used if the previous two are just not feasible for a design. Pulse drives also have a nasty reputation and many sections of space outright prohibit them. Albeit some of these restrictions don't apply to the new and more sophisticated pulse drives.

[b]Other Propulsion Types:[/b] While not the mainstream these days other forms of propulsion systems still have a niche. rockets, ion drives, plasma thrusters and so on. They are more compact and thus they are very popular for maneuvering and docking aid. Rockets in particular are still excellent in regards of heat output versus thrust and quite popular as "cheap" takeoff mechanisms from astral bodies. Another interesting propulsion system are the mass thrusters which use nothing but electromagnetic forces to launch material behind the ship as propulsion. They're the new champions in low heat propulsion and some of them use pulse mechanism more akin to a back mounted coilgun. They have many issues which prevents them from becoming mainstream but there's a growing niche for these both for stealthy military applications and alleged environment-friendly nature.
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