Wondershare PDFelement - All-in-one PDF editor
Captain Chords - Write chord progressions in your favorite DAW
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.
RapidComposer - MusicDevelopments RapidComposer: Music Prototyping and Automated Composition Software
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.
Cthulhu - VST MIDI-FX plugin for harmonic inspiration