Sonic Weaponry
One of the most exotic kind of weapons, sonic weapons emit vibrations from sound waves of various frequencies in order to not just make your usual scrub's ear drums to explode but also to disrupt anything they hit, shaking the target quite literally apart. Most commonly used by the Emperor's Children, the Eldar make use of them as well.
Noise Marine Weaponry
The warbands of the Emperor's Children (and Noise Marines in general) use sonic weapons with great frequency (heyo!), and sport three variations of the weapon.
Back in the 80s, these weapons were stylized to resemble electric guitars and keytars, making Noise Marines look like psychotic weaponised hair metal bands. This awesomeness, alas, gave way to more "modernistic" fancy guns around 4th edition.
Sonic Blaster
The basic weapon used by Noise Marines, these can be fired in two settings: a continued blast that tears at a target with the force of a Bolter round, or shorter pulses capable of quite literally rocking your socks off, and slightly better suited to mowing down infantry hordes.
Blastmaster
The Blastmaster (no, not those fancy toy guns you get from the 90's) is the Sonic Blaster turned up to 11 (heyo!). It is capable of pinning down enemy units and can fire on two settings: the varied frequency setting can be fired similarly to a heavy bolter, even on the move, though it has a slightly slower rate of fire; the single frequency setting turns it into a straight up heavy weapon that can project its ROCK over a significant target area that can damage light and medium vehicles, and kill several space marines outright. Despite its name has nothing to do with Master Blaster, who is awesome in other ways.
Doom Siren
The Doom Siren (also known as the Angry/Agony Organ) is a backpack-mounted device that can weaponize the warcries of the wearer, turning his facemelters into literal facemelters.
Sonic Shrieker
A piece of utility wargear rather than an offensive weapon, this Great Crusade-era implant was a Laer-derived implant that could work as an ersatz Mark of Slaanesh, giving those equipped a higher initiative during the first go-round in an assault. This implant doesn't make an appearance a few years down the line, either being empowered by the Chaos God Slaanesh probably led to this wargear being phased out as the Crusade built up, or was possibly "upgraded" and incorporated into the Emperor's Children implantation process for further generations of sick fucks.
The Cacophony
A weapon that was derived from the bizarre instruments commissioned by Remembrancer Bequa Kynska for her opera for the Emperor's Children (or were those instruments, looted from the blood- and semen-stained stage), this was one of the first human made sonic weapons and was designed for ear rape as well as mind rape. This Great Cursade-era weapon was used by the Emperor's Children Kakophoni (the first recognizable Noise Marines), and they look like big sonic blasters, and can be thought of as prototypical blastmasters. This was a heavy weapon that had only one firing mode that was stronger than a blastmaster's varied frenquency setting, but could only fire once and had Gets Hot!; but they had the bonus of having the capacity to inflict collateral damage to a squad that could kill most units outright.
Chaos Renegades
According to the Tome of Excess for Black Crusade, followers of Chaos besides the Noise Marines also make use of sonic weaponry, though its usage is still predominantly concentrated amongst Slaaneshi faithful. In the Screaming Vortex, sonic weaponry is most associated with the world of Ghibelline. Sonic weaponry requires energy to function, rather than ammunition, so those renegades not blessed enough to have a suit of power armor to hook them into must wear power generating backpacks.
Shrieking Pistol
This is the smallest known form of non-Legion sonic weaponry, discharging thrumming blasts of psychosonic energy. The Pirates of the Ragged Helix are mentioned as favoring this weapon for its ability to blast a target free of the limited gravity of their home range with a single shot, condemning the victim to an excruciating death as they spiral off into the depths of space.
Howler Rifle
These weapons fire intensely focused and accurate blasts of high-pitched sound, but when used at their full power, they create an acoustic onslaught that causes the wielder - and anyone else nearby - to suffer uncontrollable bleeding from their ears.
Hyperwave Clarion Cannon
The most powerful sonic wave cannon to be carried by a non-Astartes heretic, this complex but sturdy weapon uses endlessly alternating frequencies of sounds that oscillate faster than matter can withstand to reduce bones to jelly, blast ferrocrete to powder and liquefy adamantine.
Shatterscream Rounds
Originally a humble automated sentry alarm called a Screamer, Shatterscream rounds repurposes the clarions into makeshift ammo in an attempt to create a more portable and easily acquired form of sonic weaponry.
Sonic Shrieker
A modification for power armor helmets that allows the wearer to unleash disrupting screams and cries, it is "rumored to draw its origins from xenos technology" - a pretty clear reference to the infamous masks of the Eldar Howling Banshees.
Eldar
The Eldar employ a number of sonic weapons as well.
Vibro Cannon
A peculiar weapon, the Vibro Cannon builds up a charge inside itself, and then lets it fly to rip things (and people) apart. The Vibro Cannon uses multiple successive devastating sonic blasts to kill things, so the longer it stays on a target the more dead the target becomes. Comparable to the weapons used by the Noise Marines, except they use a single note or riff, instead of killing the enemy with dubstep. Essentially, the Vibro Cannon is like an opera singer using her voice to shatter a wine glass, whereas a Sonic Blaster is more like sitting right in the front row of a death metal concert. They can also combine with other Vibro Cannons to deal even more damage. As you might guess this weapon has been the butt of many a joke thanks to its name, and just as well it sounds approximately like something the Noise Marines would use, though don't tell an Eldar that...
Sonic Lance
Weaponizing sonic waves to the extreme, the Sonic Lance can shake apart even Superheavy vehicles. Due to its size this weapon can only be used by the Lynx super-heavy tank, or mounted on the Revenant Titan.