qBittorrent - Lightweight and open source torrent client that runs on all major platforms.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
Deluge - Deluge is a full-featured BitTorrent client for Linux, Unix and Windows.
eMule - eMule is a free peer-to-peer file sharing application for Microsoft Windows.
Soulseek - Soulseek® is a unique ad-free, spyware free, and just plain free file sharing application.
Transmission - Transmission has the features you expect in a BitTorrent client: encryption, a web-based interface...