The user has two holes in their elbows from which they can shoot out a burst of loud, bright light of any colour. If they just shoot one out quickly, it will be a small flash with a minor popping sound, but if the user charges them up, their flashes can be incredibly large and make a sound akin to that of a firework.

Quirk Type - Emitter (You could label it as Mutant because it puts holes in their elbows, but the main point of the quirk is what it emits, so that sort of takes priority as a label)

Best suited for- Support / Recon / Minor Offence (Mostly useful for distraction but would probably hurt if a loud, blindingly bright bang went off right in your face 😭😭)

Drawbacks - The user is not immune to the loud noise and brightness that comes off of the flash bang, so without having their ears and eyes trained to withstand their quirk, they may suffer earaches or strained eyes.

Possible Hero/Villain names -

Flashbang (obvious choice)
Flash
Bright-Light
Firework
Crackle, Snap and Bang (incase you have an overdramatic oc like Aoyama with a long hero name 😭) Or just use those names separately