There are many packet switches;
Card College/Giobbi, Marlo, Fisher, Kenner, obviously, J.K.Hartman and most big names in magic have some of their own, just look around in either books you own, or if you're looking for a list of them, then go for a search on
http://archive.denisbehr.de/, that's got most magic books published, search in there. There are so many, look around.
Tom Field