Alexicom AAC - Communication App available for IOS (iPad & iPhone) and Android, with external switch support.
ChoicePad Lite is an iPad App that features Makaton symbols.
FreeSpeech - A pretty good free communication App.
Gabby - A cheap, yet effective communication App for the iPad, iPhone and iPad Touch
Grid Player - iPad App from the makers of The Grid 2, bringing their take on a communication App to the tablet market.
Locabulary Pro - Communication App for iPad, Android and Nintendo DS that communicates phrases from within categories and utilises location services.
Predictable - Communication app for the iPad/iPhone/iPod Touch that also supports switch users
Proloquo2Go is a well thought out, comprehensive communication app for the iPad and iPhone and now incorporating full switch support.
RocketKeys - The latest offering from myVoice, giving you a type and talk App with a flexible difference.