gtk-gnutella is a server/client for the Gnutella peer-to-peer network.
Fertinke
A PDF optimizer
OcenAudio
Easy, fast and powerful audio editor
MultiWriter
Write an ISO file to multiple USB devices at once
NijsFlash
The spiritual successor to FeedReader
ProjectM
The most advanced open-source music visualizer
Video Trimmer
Video Trimmer cuts out a fragment of a video given the start and end timestamps. The video is never re-encoded, so the process is very fast and does not reduce the video quality.
Tixati
Tixati is a New and Powerful P2P System
UnGoogled Chromium
ungoogled-chromium is Google Chromium, sans integration with Google
Piper
Piper is in GTK + applikaasje om gamingmûzen te konfigurearjen.