WriteRight is a unique text editor with synonyms, antonyms and phraseology. With support for Markdown and full iCloud and Dropbox integration, WriteRight lets you easily select words and expressions to check for synonyms/antonyms, choosing from a set of A4, Letter, and Manuscript previews with colored folders.
You can find out more about WriteRight for iPhone/iPad here.
Tag Journal is a complete diary to record your thoughts and ideas with photos, videos and sound recordings. Tag Journal supports Markdown for fast text entry and formatting, and you can add multiple photos per entry. Entry/note merging helps and speeds up your writing workflow, and notes can be shared on Facebook, Twitter, iMessages, Mail, or as PDF.
You can find out more about Tag Journal for iPhone/iPad here.
Federico’s note: I personally use WriteRight (which was developed in Italy and the US) when I write on my iPad, and I truly enjoy the app’s feature set for synonyms and antonyms that lets me quickly replace an active selection in the text editor with other words.