Whalebird is a mastodon client for desktop application.
Briar
Secure messaging, anywhere.Peer-to-peer encrypted messaging and forums.
SimpleNote
The simplest way to keep notes
Marmar
Mumble is a free, open source, low latency, high quality voice chat application.
Jitsi Topaketa
Jitsi Meet is an open-source (Apache) WebRTC JavaScript application that uses Jitsi Videobridge to provide high quality, secure and scalable video conferences. Jitsi Meet in action can be seen at here at the session #482 of the VoIP Users Conference.
GTG
(GTG) is a personal tasks and TODO-list items organizer for the GNOME desktop environment
Notes
The notes plugin provides you a quick way to paste text, to write down a list of things, to leave a note to your friend, or whatever you had do with Post-It’s.
Kuaternioa
Quaternion is a cross-platform Qt5-based desktop IM client for Matrix
Elkarrizketa
Konversation is a user-friendly Internet Relay Chat (IRC) client built on the KDE Platform.
RedNotebook
RedNotebook is a desktop journal