Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
TickTick - TickTickis a cross-platform to-do list app & task manager helps you to get all things done and make life well organized.
BibDesk - BibDesk is an organizational software created to help you edit and manage your bibliography. It keeps track of your bibliographic information as well as said information's associated web links and files. Read more about BibDesk.
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
EndNote - Accelerate Your Research. Save time, stay organized, collaborate with colleagues and get published with EndNote 20.