Google docDocument writing. Create documents. If you've used Microsoft Word, this is a capable online alternative from Google.
HackMDWrite markdown documents and store them in your github account. Great online editor for writing notes in markdown
GhostA medium like blog with more customization options. Host it on your own servers or opt for the (paid) hosted version.
txtfiddle.comWrangle text files. Wrap text, add line numbers or convert it to an md5 hash. Remove the html tags from text or convert markdown to html.
Hemingway EditorAn online editor that helps you write higher quality content. It will make suggestions for improvements and help you get to a higher quality article.