@Sch123 I'd like to entertain the thought of making weapons that require some advanced scripts like stat watchers, complex particles, damage shapes et al.
Sadly, my expertise will not allow me to, especially for the likes of minigun, flamethrower and lightsaber. The latter moreso since it would require a custom model, and I have no clue how to use 3dsmax besides a few tutorials I've done over a decade ago.
As for the rifle, Rail Driver mostly does what you want, and beyond. It fires piercing "projectiles" that can go through enemies, shields, armour and even world geometry. The weapon accuracy issue seems to be persistent in vanilla as well as modded games, since, in my view, it doesn't connect unless the enemy hitboxes are aligned in a specific way, which I doubt is something I can fix, nor would want to, since the base weapon I made is already arguably overpowered, considering it shoots through everything and, with "force attack", doesn't require line of sight at all.
Moving on.
Laser weapons are feasible, but would most likely require making new unit types so they can utilise custom firing particles and damage shapes. Without that, those seem to be more or less hardcoded and I never had any luck finding which files are referenced for firing sequences and so on.
There's already a mortar-esque projectile [under "missiles"] in the stock game that could be reused for what you want, but the technicalities behind it don't make it all that useful, since it has both maximum and minimum strike range, thus eliminating a lot of applications for it.
If you want an assault rifle that fires in bursts, I wouldn't have a clue where to start. If you want something that's faster than a shotgun but with less damage, anyone can do it in GUTS by dropping damage graph offset and increasing weapon speed.
Stun gun, while amusing at first, could be either gamebreaking or completely useless. Useless against bosses because they got stun resistance, gamebreaking on standard mobs and even champions, since you can just stunlock everything to death, especially if it deals damage on top of being able to stun enemies.
For wind blade, same case as with burst assault rifles - I wouldn't even know how to start this sort of thing.
Crossbow splash damage can be done via missiles. Bleed or whatever other debuff can be/might be done with affixes with unitthemes that activate via transfer. I think...
Fist blast, again, stat watchers and specific game events. Way above my league. Same for thrown weapons.
Now, being a party pooper aside, what I was initially asking for was some suggestion on vanilla player class skills to dumb down into a single-level skill which I could then use as a proc.
Example: a greathammer, which is a weapon suitable for an engineer, using emberquake, which is an engineer skill.
Bottom line is, a class-themed weapon that doesn't actually require you to be that class to use it.
@steffire3 unless I got it wrong, a pistol cannot be both a pistol and a melee weapon without some funky unittype/item hierarchy editing.
If you meant a pistol that's got microscopic range but still works like one and gets ranged bonuses, then that should only be a matter of shrinking strike/approach range to those of a claw/sword.