i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
dwm - dwm is a dynamic window manager for X. It manages windows in tiled, monocle and floating layouts. All of the layouts can be applied dynamically, optimising the environment for the application in use and the task performed.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Openbox - Openbox is a highly configurable, next generation window manager with extensive standards support.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.