Below is a list of letter combinations skipped from the blue HAA- series forward.
The reason for most of the omissions is obvious - but there are a few mysteries...
This list starts at GAA, issued back in 1990.
The blue plates still used I and O on passenger plates, which provided more opportunities for skipping combinations.
1992 BASE (3M)
There were no skipped combinations in the 7-digit series between AAA1000 and ADJ9999.
1999 BASE (3M)
2001 BASE (AVERY)
2004 BASE (3M-2)
2007 BASE (NO STICKER BOXES)
2010 BASE (A10-AAA)
2014 BASE (FLAT)
All of the -FU series was skipped except for (strangely) FUA. Aaaww, you're no FUN anymore...
This list covers plates up to and including the JHZ suffix.