Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Adobe Reader - Adobe Acrobat Reader is a free tool for viewing documents that have been stored in Adobe's Portable Document Format (PDF).
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
SysTools OST Viewer - Free Outlook OST Viewer Software is used to open OST file with attachments. OST Reader Tool provide a complete solution to view corrupted, orphaned OST files.
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip
PDF Reader Pro - PDF Reader Pro is an all-in-one PDF office supporting to Read, Annotate, Edit, OCR, Convert, Create & Fill Form, Sign PDFs, TTS on Mac, iOS, Android, and Windows.