Clementine
Clementine – multiplatform free and open source modern music player and library organizer
Akregator
Akregator – free and open source is a news feed reader, that supports RSS and Atom feed formats with a built-in web browser
Liferea
Liferea – free and open source web feed reader/news aggregator, that supports RSS and Atom feed formats with a embedded web browser for Linux
Persepolis Download Manager
Persepolis – a simple cross-platform free and open source download manager with a built-in video downloader
uGet
uGet – cross-platform free and open source light but powerful download manager
Geary
Geary – simple free and open source email client for GNOME with the necessary set of functions for comfortable work with
Thunderbird
Thunderbird – free and open source cross-platform email, news, and chat client, and when installing the Lightning extension, and with a calendar
KTorrent
KTorrent – free and open source BitTorrent client by KDE. It allows you to run multiple torrents at the same time and its features can be extended by plugins
qBittorrent
qBittorrent – cross-platform free and open source software alternative to µTorrent. BitTorrent file sharing network client. Torrent client with a built-in search engine
Psi+
Psi+ – cross-platform powerful XMPP client, implementation of the Psi jabber client with newer features and faster bug fixes