Task Management & To-do lists
Traggo
Traggo is a tag-based time tracking tool. In Traggo there are no tasks, only tagged time spans. (Source Code).
TimeTagger
An open source time-tracker based on an interactive timeline and powerful reporting. (Demo, Source Code).
solidtime
Modern time tracking application for freelancers and agencies. (Source Code).
Kimai
Track work time and print out a summary of your activities on demand. (Demo, Source Code).
Ever Gauzy
Open business management platform for collaborative, on-demand and sharing economies (ERP/CRM/HRM/ATS/PM). (Demo, Source Code).
Beaver Habit Tracker
Habit tracking app to save your precious moments in your fleeting life. (Demo).
ActivityWatch
Automatically track how you spend time on your devices. (Source Code).
Wekan
Open-source Trello-like kanban. (Source Code).
Vikunja
The to-do app to organize your life. (Demo, Source Code).
Tracks
Web-based application to help you implement David Allen’s Getting Things Done™ methodology. (Source Code).
Tegon
Dev-first issue tracking tool (alternative to Jira, Linear). (Source Code).
Taskwarrior
Taskwarrior is Free and Open Source Software that manages your TODO list from your command line. It is flexible, fast, efficient, and unobtrusive. It does its job then gets out of your way. (Source Code).