More than once, the eponymous protagonist of the Scott Pilgrim series has used the power of rock against his enemies, most notably at the ends of volumes one and three. Since he himself isn't that great a musician, usually other people are helping him out. And the music alone isn't enough to truly defeat the opponent, but it does weaken him sufficiently for Scott to take him out with some good old-fashioned fisticuffs.
Additionally, Matthew Patel could summon hordes of minion girls with his Bollywood-style fighting, and Crash and the Boys, rival group to Scott's band Sex Bob-Omb, can put audiences into a literal daze with their music.
The infamously deplored weekly series Countdown had one good thing: when the Pied Piper uses The Power of Rock to destroy an entire planet.
Actually, he doesn't destroy the planet Apokalips, he just drives away Brother Eye/OMAC, the giant space entity. The planet always has those huge spouts of flame coming from it.
Which, considering everything he'd been through by that point, is still pretty darn impressive.
Occasional X-Men member Dazzler's powers work by converting sound to light (which she can then use as laser beams). Naturally, she picked a musical career. Fighting evil with the power of... erm... Disco.
The Ultimate Marvel version is a punk rocker. Imagine: instead of many sparkly lights, it's one giant Beam Spam!
An issue of the Marvel ComicsThe Transformers series had Soundwave taking this trope literally when he harnessed the sonic power of a Bruce SpringsteenBrick Springhorn concert to make energon cubes.
In The Power of Shazam! issue 18, Mr. Mind was just made into the last surviving member of his species, and to exact his revenge on the Big Red Cheese, he possesses the Wizard, who, running away from Mr. Mind, had fled into a sound studio. Knowing the worm species has a weakness against loud sounds, Captain Marvel gives the Wizard a headset, picks up one of the electric guitars laying around, and starts to play like "Hendricks".
In Joss Whedon's one-shot comic Sugarshock!, a band mistakes an invitation to an alien tournament for a Battle of the Bands and proceeds to try to use the power of rock. Played with in that the band wins not through epic rock but with the saddest song in the world. One voice. One guitar. In-universe Tear Jerker. Only squirrels were unaffected because squirrels have no souls.
Image Comic's "The Amazing Joy Buzzards" is about a rock band and their luchadore friend who battle supernatural hipsters, demonic robots, and fallen angels.
Asterix and Obelix's village bard has made the Normans run away in fear and make it rain in an Indian draught.
