The Noise Marines blast the enemy with deafening noise, a way-beyond-sanity version of this trope. Back in older and funnier editions, they were equipped with electric guitars.
The Sisters Of Battle have the Exorcist, a rocket-firing artillery platform in the form of a pipe organ, with a Sister driving the tank and a servitor playing the organ and/or launching the missiles.
Starchildren: Velvet Generation has glam rock aliens come to the future where the danger of emotions means that Rock has been suppressed by the Culture Police. The titular Starchildren want to free the mass of humanity from their emotional blinders with the power of rock, and their alien magic powers.
Cyberpunk 2020 has the Rockerboy "class", who's special skill is "charismatic leadership". It allows him to influence ever greater crowds of people.
Dungeons & Dragons has, for some years, sported a Bard class. Bards do a little bit of everything... and also boast The Power of Rock.
Indeed, an epic level bard has at least a 30% chance of secretly being Freddie Mercury.