RSSme - RSSme is free, lightweight and user-friendly RSS editor.
Wondershare PDFelement - All-in-one PDF editor
Feed Launch .NET - Feed Launch .NET is an open-source feed editor for RSS 2.0 and ATOM 1.0 Feeds.
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.
Feeder by Reinvented Software - Feeder is for creating, editing and publishing RSS feeds on macOS.
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.