Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
Wondershare PDFelement - All-in-one PDF editor
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.