Sticking with the Slug Club, do you remember seeing a pair of identical twins in the background? They don't really say or do very much, but they're always there, indulging in a bit of physical comedy. Some sources name the characters as Flora and Hestia Carrow. One of them is played Amber Evans, seen here as she was at the time, and all grown up today.
She never appeared in any medium without her sister, and indeed her only IMDB credit other than her Harry Potter work is for a movie called "Signs of Life", in which being an identical twin was also an essential part of getting the role. Amber didn't stay in the entertainment business for long after her time on Harry Potter ended, and she was last heard of studying to become a doctor. Aside from that, she seems to have vanished from the internet completely. A trick worthy of Harry himself!