Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

FastStone Capture - A powerful, lightweight, yet full-featured screen capture tool that allows you to easily capture...

Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.