Who were the Gryffindor prefects during Harry's 4th year (Goblet of Fire)? One of these prefects gave the Weasley twins the Gryffindor password.
We barely even know who were the Gryffindor students in that year, let alone which two were made prefects.
The only two confirmed Gryffindor students from that year were Cormac McLaggen and Katie Bell. It's possible that one or both of them were made prefect, but I'd think that the lack of any mention of this when discussing them would be an indicator otherwise.
There's around thirty other Gryffindor students we know of who could have been in that year, and if so the prefects could have been two of them.
The two prefects could also just be students that we've never heard of. (This is the most likely scenario.)
As far as I can discern, Rowling has not offered any more information in any of her books, interviews, pottermore writings, or tweets.