Rocket.Chat - Free, Open Source, Enterprise Team Chat

Joplin - an open source note taking and to-do application with synchronisation capabilities

Standard Notes | End-To-End Encrypted Notes App

GitHub - greggigon/my-personal-kanban: This is a one page HTML/JavaScript application for people who would like to use simple and basic Kanban board for their personal stuff

Jami

Home - Pencil Project

Ferdi

kofigumbs/multi: Create a custom, lightweight macOS app from a group of websites

Focalboard: Open source alternative to Trello, Asana, and Notion

Spectre: Passwords, Privacy-first