Manuskript - Open-source tool for writers.
Arcweave - Arcweave is the first browser based cloud professional tool for game and narrative design.
StoryMill - Developers and publishers of Mac, Win, and iOS productivity, home and office and writing software such as MacGourmet, Paperless and many more. Based in MN.
Dialogue Designer - An easy to use but powerful tool for creating branching dialogues for games.
Novelize - Novelize is an online novel writing app designed to keep authors on track.
Scrivener - Scrivener is a content-generation tool for composing and structuring documents.