ScreenTray - A better way to capture, annotate and share screenshots
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.
Annotate by Convergely - Easily annotate images you get on Slack - just like Skitch
Wondershare PDFelement - All-in-one PDF editor
Weava - Workspace to highlight, organize & collaborate on your research articles.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.