Seconding org-mode, with the suggestion of Spacemacs to minimize the barrier of entry into emacs. org is awesome for anything you could want to do with text; lists, tables, calendars, project management, word processing, you name it. If there's something you want to do with your text, it's possible to do with org, and if the functionality doesn't exist yet anyone (who can program) can extend it and add the functionality. It's incredibly easy to work with the output as well, I know of people who publish ebooks straight from their org output. As a bonus, it's free in every sense of the word. The only downside is getting started. If you aren't familiar with keyboard based navigation or vim style motions if using Spacemacs / evil-mode you'll feel like you're stuck and have no idea how to use this text editor from '85. It feels incredibly unintuitive until it doesn't. If you edit text daily, however, it's absolutely worth it.