Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
UpNote - A beautiful and clean cross-platform app for notes organizer
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Notesnook - Notesnook is a simple and private note taking app that keeps your notes organized and synced on your phone, tablet and computer.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
todoZero - A powerful to-do and note app for busy people.