Guns

There will be a focus on four kinds of personal firearms in the setting: Projectile, Laser, Plasma and Sonic.

Sonic weapons have replaced tazers for the most part, and are very popular in ship-to-ship boarding actions, as there is no risk of penetrating the hull and sonics ignore body armor that isn't heavily sound-proofed (and even then the vibrations will rattle your skull a bit). They're the non-lethal main, basically.

Lasers are, for the most part, in the form of tools modified into weapons or sniper/hunting rifles, since in normal combat being able to see where you're shooting is kind of important, and because they're liable to scatter and disperse in the kind of dust and smoke you get in large-scale combat. It's often used by assassins, but also by hunters. Lasers generally sound like loud pops or cracks followed by faint buzzing, with the more powerful types of beam-weapons being as loud as conventional firearms in our modern world.

Plasma weaponry serves much the purpose of lasers in most space opera, the bolts of superheated plasma you fire are slow enough to be visible and look awesome, and most plasma weapons are indeed called "blasters". Plasma weapons have recoil and can overheat the barrel, and yes, they do make 'pew, pew'-sounds. Oh yeah, you get green, white, blue, red bolts. Depends on the gas used.

Projectile weapons mainly come in three varieties, flechette, caseless chemical propellant and electromagnetic coil-weapons. Flechette weapons are often used for those wanting something with punch that incapacitates rather than kills, most police forces around the galaxy uses some variety of them, with everything from tranq-darts to versions of smart-bullet beanbag ammo that knocks out but leaves no lasting injuries. Most flechette weapons use compressed air or other gases to propel the ammunition, and it's not 100% safe, you still get occasional fatalities. Still, as most humans say, better to have trigger-happy law-enforcement agencies 78% less likely to be able to kill you than what we used to have.
Caseless is basically regular firearms, but without shell casings, the issues had with such weapons having been solved at this point. Caseless ammo basically has cartridges where the body is the propellant itself, and the bullet is directly fastened to it, this allows for smaller cartridges and no flying shell casings. These guns still have to eject the burning gases and particles, so they still need about the same amount of moving parts, but at least the load of a pistol is bigger, and calibers can be larger. Firearms with caseless, chemically propelled ammunition are extremely common, but for understandable reasons they're rarely used in spaceships or on environments in space.
Electromagnetic coil-weapons are heavy-duty stuff, the equivalent of a Desert Eagle .50 but more accurate and a hell of a lot deadlier. Ironically, the projectiles are much smaller. Attempts at making larger coil-guns than pistols have yielded varying results, for the most part the weapons require wielders who can handle the recoil, which means either people in military-grade powered armor or species much stronger than humans.