Na, I didn't even look on ICC...
They're all the contracted players, and players who've either played, or been named in the squads this season.
That's why there's dudes like Nick Horsley and Mark Craig who haven't played in two years, but have been in the 12/13 man squads for a few matches this season, so I decided to include them.
Half the teams don't update their websites as well, so that's rather annoying.
Also I wasn't sure who to include as all-rounders, the likes of Morgan, Neesham, van Beek, Bracewell, Rance, and Wheeler are all young dudes who've been all-rounders at age group level, and bat like 7/8/9 for their provinces, but are yet to really do anything with the bat at domestic level, I just included them as all-rounders in the end.
Despite Michael Parlane being called a wicket-keeper by cricinfo, he's never actually kept at domestic level, he just kept in a few random matches back in the early 90's before he made his domestic debut, so I'm not going to allow him to keep this season.
Marc Calkin's another interesting person, he kept on debut, but has also bowled in three out of his six T20 matches.