Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.
Taiga is the easy and intuitive yet powerful agile project management tool for multi-functional teams. Taiga has a best in class Sprint task board, and you can seamlessly migrate to Kanban if needed.
Kanboard is a free and open source Kanban project management software.
GanttProject is a cross-platform desktop tool for project scheduling and management. It runs on Windows, Linux and MacOSX, it is free and its code is opensource. What can it do?
Phabricator is a collection of open source web applications that help software companies build better software.
Effective June 1, 2021: Phabricator is no longer actively maintained.https://admin.phacility.com/phame/post/view/11/phacility_is_winding_down_operations/
Trac is an enhanced wiki and issue tracking system for software development projects. Trac uses a minimalistic approach to web-based software project management. Our mission is to help developers write great software while staying out of the way.
Mantis Bug Tracker is a free and open source, web-based bug tracking system. It is written in the PHP scripting language and works with MySQL, MS SQL, and PostgreSQL databases and a webserver. MantisBT can be installed on Windows, Linux, Mac OS, OS/2, and others.
There can be more than Notion and Miro. Affine is a next-gen knowledge base that brings planning, sorting and creating all together. Privacy first, open-source, customizable and ready to use.
ZenTao is an open source project management tool, supporting Scrum. It integrates product management, project management, bug management and QA management, etc., covering all lifecycle of software development.