qBittorrent - Lightweight and open source torrent client that runs on all major platforms.
gtk-gnutella - gtk-gnutella is a server/client for Gnutella.
Deluge - Deluge is a full-featured BitTorrent client for Linux, Unix and Windows.
LimeWire - LimeWire is a free peer-to-peer file sharing platform that is available to use on Windows, Mac OS and Solaris platforms.
BitTorrent - BitTorrent is a peer-to-peer program developed by Bram Cohen and BitTorrent, Inc.
eMule - eMule is a free peer-to-peer file sharing application for Microsoft Windows.