Trelby is a free and open source screenwriting program which focuses on providing a simple, uncluttered interface to writing screenplays.
Developed by Trelby.org
Celtx is media pre-production software, designed for creating and organizing media projects like screenplays, films, videos, stageplays, audio plays, document…
yWriter is a word processor which breaks your novel into chapters and scenes, helping you keep track of your work while leaving your mind free to create.