Purp - A smart to-do list and goal tracker app
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Nirow - Habit tracking: Automated, Siri-ed, Calendar-ed, and More!
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.
Things - Things is an easy to use task manager.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .