A simple torrent client.
sombina
Fragments is an easy to use BitTorrent client for the GNOME desktop environment. It is usable for receiving files using the BitTorrent protocol, which enables you to transmit huge files, like videos or installation images for Linux distributions.
safo-drano
Deluge is a fully-featured cross-platform BitTorrent client. It is Free Software, licensed under the GNU GPLv3+ and adheres to freedesktop standards enabling it to work across many desktop environments.
WebTorrent
App to connects to both BitTorrent and WebTorrent peers and even play the files before downloading.
Transmission
Transmission is a cross-platform BitTorrent client.