Using the sweater number archive at Hockey-Reference as a guide,we can see that since the 1998-99 season, no player has ever worn the number 98. That's the only number not to have been worn.
We can also see that only two non-goalies have worn the number 30. Andrei Zyuzin, who wore #30 as a defenseman in Tampa for three seasons (1999/2000-01/02) and Jean-Francois Jomphe who in 1999 played six games at center in Montréal with the 30 sweater.
Their sweater number archives don't go further back than the 1998-99 season, but it can be a fun way to waste some time.
I have some amateur plumbing to take care of in my bathroom today. I'm 100% confident that I'll mess it up. At some point later today, I'll go through the all-time Hurricanes sweater numbers and pick my favorites.