Moodnotes - Capture your mood and improve your thinking habits
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Moodica - Oddly satisfying videos to relax your brain.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Realifex - Personal diary for positive change
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.