Fiddlesticks' drain.
Nocturne's fear, IIRC, creates a laser effect with the leash, and the DARKNESS makes for fun light shows.
Amumu's bandage. His ult is all light-based, if you don't think bandages are lasers (for whatever stupid reason).
If nothing else fits, Lee Sin the blind monk would be an amusing contrast to the rest of the team.
Others you may have missed:
Malzahar's ult is an eye laser, and I think his Q can be seen as lasers.
Morgana's ult fires beams.