UPDF - UPDF is a free, unique, productive, and delightful PDF editor for Windows, Mac, iOS, and Android.
Wondershare PDFelement - All-in-one PDF editor
calibre - Ebook manager, viewer & converter
Foxit PhantomPDF - Edit PDF files with our feature-rich PDF Editor. Download Foxit PDF Editor to convert, sign, scan / OCR & more. A speedy PDF Editor alternative to Adobe Acrobat.
OverDRIVE - Make workspaces and sites automatically from Google Drive
Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.