Final Draft is a screenwriting software for writing and formatting a screenplay to meet submission standards set by theater, television and film industries. The program can also be used to write documents such as stageplays, outlines, treatments, query letters, novels, graphic novels, manuscripts, and basic text documents.
Celtx is media pre-production software, designed for creating and organizing media projects like screenplays, films, videos, stageplays, audio plays, documentaries, machinima, comics, games, and podcasts
Trelby is a free and open source screenwriting program which focuses on providing a simple, uncluttered interface to writing screenplays. It is a rebranding of an older screenwriting program called Blyte. It currently runs on both Windows and Linux platforms.