Taskful - Deadlines, meet your match.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Calendarist - Time blocking companion for Google Calendar
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.
Gone - An ephemeral to-do list
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .