Sonic Weaponry
One of the most exotic kind of weapons, sonic weapons emit vibrations tooled 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.
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 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.
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.