There are several software options for screenwriters, some of the most popular ones are:

1. Final Draft: a leading screenwriting software that is used by many professional screenwriters and in film and television industry. It offers features such as script formatting, collaboration tools, and script analysis.

2. Celtx: a free, open-source software that provides basic screenwriting features and also includes storyboarding, production scheduling, and budgeting tools.

3. StudioBinder: a cloud-based software that includes a comprehensive suite of production tools including storyboarding, shot list creation, and scheduling.

4. WriterDuet: a cloud-based collaboration platform that allows multiple writers to work on the same script in real-time. It also includes script formatting, revision tracking, and production schedules.

5. Fade In: a cross-platform, affordable screenwriting software that offers script formatting, real-time collaboration, and production reports.

Ultimately, the best software for screenwriters depends on their specific needs and preferences. It’s recommended to try out a few options to determine which works best for you.