Katarina Szarbo would have been a seventh year Ravenclaw in the 1997-1998 school year but she was a muggleborn so could not be present for the final year of her Hogwarts education. She disappeared and it is unknown what became of her.
Katarina was Anglo-Hungarian; her grandparents fled when Hitler and Stalin were (as Andy says) "tangoing" across Eastern Europe. Katarina spoke Russian and Hungarian along with English.
Katarina attended the Yule Ball with Anthony Goldstein.