LibreOffice is a complete open source alternative to Microsoft Office. It includes, Writer (word processing), Calc (spreadsheets), Impress (presentations), Base (databases), Math (formula editing), and Draw. Draw is an alternative to Microsoft Publisher for creating multi-page layouts. Open, edit, and create many different file formats including .PUB, .PDF, .DOC, .DOCX, and many more!
Scribus is an open-source alternative to InDesign. With a user-friendly interface, Scribus includes a variety of professional publishing features, such as CMYK color support, spot colors, ICC color management, and PDF creation. Scribus also includes powerful vector drawing tools and support for importing and exporting many different file types.
Pinta is a lightweight photoshop-style drawing and editing program. Not quite as complex and feature packed as Krita or Photoshop, yet still includes a wide variety of familiar features including, layers, adjustments, effects, clone-stamping, gradients, text and more. Users of Photoshop will feel at home with a similar tool layout and workspace.
RawTherapee is an advanced raw image processor. The program contains a wide range of professional features for processing digital photography including RAW photos from a digital camera.
Believe it or not, most commercially available software has a FREE twin! (Or at least distant cousin!)