750 Words is described as 'online plain text editor with autosave and fullscreen edit options, 750 Words also lets you track your progress and earn points for achievements. Login with Google, Yahoo or Facebook Connect' and is an website in the News & Books category. There are more than 10 alternatives to 750 Words, not only websites but also apps for a variety of platforms, including Mac, Windows, iPhone and iPad. The best alternative is TextMaker, which is free. Other great sites and apps similar to 750 Words are Byword (Paid), OmmWriter (Paid), Atlantis Word Processor (Freemium) and WriteNext (Free).
writingtherapy.io is a free writing platform that allows you to write about your feeling, goals, and desires daily. It has many good features but my favorites are writing prompts and the progress graph.