Manuskript - Open-source tool for writers.
Scrivener - Scrivener is a content-generation tool for composing and structuring documents.
Celtx - Celtx is a scriptwriting software platform with applications in a wide range of mediums but that specializes in helping screenwriters.
Storyline Creator - An elegant tool for authors to write, organize and visualize their stories.
Trelby - The free, multiplatform, feature-rich screenwriting program!
CreaWriter - Full screen text editor distraction free writing enviroment.